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Articoli di riviste sul tema "ADN ligase IV"

Autore: Grafiati

Pubblicato: 7 settembre 2022

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1

Tomkinson, Alan E., Tasmin Naila e Seema Khattri Bhandari. "Altered DNA ligase activity in human disease". Mutagenesis 35, n. 1 (20 ottobre 2019): 51–60. http://dx.doi.org/10.1093/mutage/gez026.

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Abstract The joining of interruptions in the phosphodiester backbone of DNA is critical to maintain genome stability. These breaks, which are generated as part of normal DNA transactions, such as DNA replication, V(D)J recombination and meiotic recombination as well as directly by DNA damage or due to DNA damage removal, are ultimately sealed by one of three human DNA ligases. DNA ligases I, III and IV each function in the nucleus whereas DNA ligase III is the sole enzyme in mitochondria. While the identification of specific protein partners and the phenotypes caused either by genetic or chemical inactivation have provided insights into the cellular functions of the DNA ligases and evidence for significant functional overlap in nuclear DNA replication and repair, different results have been obtained with mouse and human cells, indicating species-specific differences in the relative contributions of the DNA ligases. Inherited mutations in the human LIG1 and LIG4 genes that result in the generation of polypeptides with partial activity have been identified as the causative factors in rare DNA ligase deficiency syndromes that share a common clinical symptom, immunodeficiency. In the case of DNA ligase IV, the immunodeficiency is due to a defect in V(D)J recombination whereas the cause of the immunodeficiency due to DNA ligase I deficiency is not known. Overexpression of each of the DNA ligases has been observed in cancers. For DNA ligase I, this reflects increased proliferation. Elevated levels of DNA ligase III indicate an increased dependence on an alternative non-homologous end-joining pathway for the repair of DNA double-strand breaks whereas elevated level of DNA ligase IV confer radioresistance due to increased repair of DNA double-strand breaks by the major non-homologous end-joining pathway. Efforts to determine the potential of DNA ligase inhibitors as cancer therapeutics are on-going in preclinical cancer models.

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Gu, Jiafeng, Haihui Lu, Brigette Tippin, Noriko Shimazaki, Myron F. Goodman e Michael R. Lieber. "XRCC4:DNA ligase IV can ligate incompatible DNA ends and can ligate across gaps". EMBO Journal 26, n. 14 (25 luglio 2007): 3506–7. http://dx.doi.org/10.1038/sj.emboj.7601729.

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3

Tseng, Hui-Min, David Shum, Bhavneet Bhinder, Sindy Escobar, Nicholas J. Veomett, Alan E. Tomkinson, David Y. Gin, Hakim Djaballah e David A. Scheinberg. "A High-Throughput Scintillation Proximity-Based Assay for Human DNA Ligase IV". ASSAY and Drug Development Technologies 10, n. 3 (giugno 2012): 235–49. http://dx.doi.org/10.1089/adt.2011.0404.

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4

Malu, Shruti, Pablo De Ioannes, Mikhail Kozlov, Marsha Greene, Dailia Francis, Mary Hanna, Jesse Pena et al. "Artemis C-terminal region facilitates V(D)J recombination through its interactions with DNA Ligase IV and DNA-PKcs". Journal of Experimental Medicine 209, n. 5 (23 aprile 2012): 955–63. http://dx.doi.org/10.1084/jem.20111437.

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Artemis is an endonuclease that opens coding hairpin ends during V(D)J recombination and has critical roles in postirradiation cell survival. A direct role for the C-terminal region of Artemis in V(D)J recombination has not been defined, despite the presence of immunodeficiency and lymphoma development in patients with deletions in this region. Here, we report that the Artemis C-terminal region directly interacts with the DNA-binding domain of Ligase IV, a DNA Ligase which plays essential roles in DNA repair and V(D)J recombination. The Artemis–Ligase IV interaction is specific and occurs independently of the presence of DNA and DNA–protein kinase catalytic subunit (DNA-PKcs), another protein known to interact with the Artemis C-terminal region. Point mutations in Artemis that disrupt its interaction with Ligase IV or DNA-PKcs reduce V(D)J recombination, and Artemis mutations that affect interactions with Ligase IV and DNA-PKcs show additive detrimental effects on coding joint formation. Signal joint formation remains unaffected. Our data reveal that the C-terminal region of Artemis influences V(D)J recombination through its interaction with both Ligase IV and DNA-PKcs.

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Srivastava, Abhishek, Neetu Srivastava, Umesh NathTripathi e Afshan Siddiqui. "Synthesis and Characterization of Mixed Ligand Complexes of Zirconium(IV) with Sulphur, Nitrogen and Oxygen Donor Ligands". Chemistry & Chemical Technology 13, n. 1 (5 marzo 2019): 23–32. http://dx.doi.org/10.23939/chcht13.01.023.

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Ahmadov, I. A., e A. M. Pashajanov. "SPECTROPHOTOMETRIC RESEARCH INTO MULTI-LIGAND COMPLEXES FORMED BY ZIRCONIUM (IV) WITH STILBAZOLE AND CETYLPYRIDINIUM CHLORIDE". Chemical Problems 19, n. 4 (2021): 241–49. http://dx.doi.org/10.32737/2221-8688-2021-4-241-249.

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This study deals spectrophotometric analysis of the multi-ligand complex of zirconium (IV) with stilbazole and cetylpyridinium chloride. Dichloroethane was selected as the extragent and acetonitrile as the dispersant solution. Optimal conditions for the complex formation were identified. The results of the extraction process and complex formation were calculated statistically withPlackett Burman design and central composite design (via the Minitab 19 program). The values obtained showed that experimental results can be expressed as statistical results. Most important factors influencing absorption during complex formation were pH and ligand content. To obtain the maximum absorption, pH should be 4.5 and the ligand content should be 300 µL. The stoichiometric composition of the components in the complex was determined by various methods. The interval of subordination to Baer's law was 2-7.6 μg mL-1 , the molar light absorption coefficient was 2.6 × 104 L Mol-1 cm -1 , λmax = 590nm. A highly selective methodology was developed to determine the zirconium (IV) micronutrients in water samples.

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Gudzenko, O. V., N. V. Borzova, L. D. Varbanets, I. I. Seifullina, O. A. Chebanenko e O. E. Martsinko. "Effect of Different Ligand and Different Ligand Heterometal Xylaratohermanates on the Activity of α-L-Rhamnosidases Eupenicillium erubescens, Cryptococcus albidus and Penicillium tardum". Mikrobiolohichnyi Zhurnal 83, n. 3 (17 giugno 2021): 35–45. http://dx.doi.org/10.15407/microbiolj83.03.035.

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α-L-Rhamnosidase [EC 3.2.1.40], enzyme of the hydrolase family has a wide range of applications: in the food industry, for example, in winemaking to improve the quality and aroma of wines, in the production of citrus juices and drinks to remove bitter components (naringin) that improves the quality and nutritional value of these products; in research as an analytical tool for studying the structure of complex carbohydrate-substituted biopolymers. For the successful use of α-L-rhamnosidases in various biotechnological processes, an important aspect is the development of ways to increase their activity. The main factors affecting the growth and metabolism of microorganisms, including the synthesis of enzymes, are the physicochemical conditions of cultivation, the composition of the nutrient medium, the introduction of substances that raise the yield of the enzyme, which is manifested in an increase in its activity. At present, one of the priority directions of modern research is the study of the effect of various effector compounds that are capable to modify the studied enzymatic activity. In this work, which is a continuation of previous studies, a number of mixed-ligand and mixed-ligand-different-metal coordination germanium compounds of with xylaric acid (H5Xylar), 1,10-phenanthroline (Phen), 2,2-bipyridine (bipy) and ions of 3d-metals (Fe2+, Ni2+, Cu2+, Zn2+) were selected as effectors. Study of the effect of these complexes on the activity of Eupenicillium erubescens, Cryptococcus аlbidus and Penicillium tardum α-L-rhamnosidases were the aim of this work. Methods. The objects of research were α-Lrhamnosidases from Eupenicillium erubescens 248, Cryptococcus albidus 1001, and Penicillium tardum IMV F-100074. The α-L-rhamnosidase activity was determined by the Davis method using naringin as a substrate. We used 12 coordination compounds of germanium as modifiers of enzyme activity, the composition and structure of which were established using a combination of physical and chemical research methods: elemental analysis, thermogravimetry, IR spectroscopy and X-ray structural analysis. Structures of seven compounds are deposited in the Cambridge Crystallographic Database. When studying the effect of various compounds on the activity of enzymes, concentrations of 0.1 and 0.01% were used, exposure times were 0.5 and 24 hours. The test compounds were dissolved in 0.1% dimethyl sulfoxide. UV-spectra of absorption of native and chemical modified preparations of the enzymes were studied by spectrophotometer-fluorimeter DeNovix DS-11 in the range of 220–340 nm, concentration of the enzyme preparation 1.0 mg of protein/mL. Results. Analysis of the totality of the obtained data (exposure time 24 h, concentration 0.1%) regarding the effect of the studied compounds on the activity of E. erubescens, C. albidus and P. tardum α-L-rhamnosidases showed that the influence of the studied modifiers for the activity of α-L-rhamnosidases varies depending on the producer strain. Our data allow us to present the following series of modifiers in accordance with an increase in their effect on the activity of enzymes of different producers: E. еrubescens: 12 < 11 < 5 < 3 < 4=10 < 1 < 3 < 8 < 2 < 6 < 7; C. albidus: 10 < 11 < 12 < 9 < 3 < 1=5 < 8=4 < 2 < 6 < 7; P. tardum: 12=2 < 3 < 4 < 11 < 5 < 8 < 1 < 9 < 6 < 10 < 7. Conclusions. The results obtained allow us to conclude that compound (7)(-tris(bipyridine) nickel(II) μ-dihydroxyxylaratogermanate(IV)) is the most effective activator of α-L-rhamnosidases of all three micromycete strains, compound (6)(tris(phenanthroline)nickel(II) μ-dihydroxyxylaratogermanate(IV)) − on α-L-rhamnosidase from E. erubescens and C. albidus, while compound (10)-(copper(II) μ-dihydroxyxylaratogermanate(IV)-cuprate(II)) − only of P. tardum α-L-rhamnosidase.

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Dallaire, Frédéric, Paola Blanchette e Philip E. Branton. "A Proteomic Approach To Identify Candidate Substrates of Human Adenovirus E4orf6-E1B55K and Other Viral Cullin-Based E3 Ubiquitin Ligases". Journal of Virology 83, n. 23 (16 settembre 2009): 12172–84. http://dx.doi.org/10.1128/jvi.01169-09.

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ABSTRACT It has been known for some time that the human adenovirus serotype 5 (Ad5) E4orf6 and E1B55K proteins work in concert to degrade p53 and to regulate selective export of late viral mRNAs during productive infection. Both of these functions rely on the formation by the Ad5 E4orf6 protein of a cullin 5-based E3 ubiquitin ligase complex containing elongins B and C. E1B55K is believed to function as the substrate recognition module for the complex and, in addition to p53, Mre11 and DNA ligase IV have also been identified as substrates. To discover additional substrates we have taken a proteomic approach by using two-dimensional difference gel electrophoresis to detect cellular proteins that decrease significantly in amount in p53-null H1299 human lung carcinoma cells after expression of E1B55K and E4orf6 using adenovirus vectors. Several species were detected and identified by mass spectroscopy, and for one of these, integrin α3, we went on in a parallel study to confirm it as a bone fide substrate of the complex (F. Dallaire et al., J. Virol. 83:5329-5338, 2009). Although the system has some limitations, it may still be of some general use in identifying candidate substrates of any viral cullin-based E3 ubiquitin ligase complex, and we suggest a series of criteria for substrate validation.

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Schwartz, Rachel A., Seema S. Lakdawala, Heather D. Eshleman, Matthew R. Russell, Christian T. Carson e Matthew D. Weitzman. "Distinct Requirements of Adenovirus E1b55K Protein for Degradation of Cellular Substrates". Journal of Virology 82, n. 18 (9 luglio 2008): 9043–55. http://dx.doi.org/10.1128/jvi.00925-08.

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ABSTRACT The E1b55K and E4orf6 proteins of adenovirus type 5 (Ad5) assemble into a complex together with cellular proteins including cullin 5, elongins B and C, and Rbx1. This complex possesses E3 ubiquitin ligase activity and targets cellular proteins for proteasome-mediated degradation. The ligase activity has been suggested to be responsible for all functions of E1b55K/E4orf6, including promoting efficient viral DNA replication, preventing a cellular DNA damage response, and stimulating late viral mRNA nuclear export and late protein synthesis. The known cellular substrates for degradation by E1b55K/E4orf6 are the Mre11/Rad50/Nbs1 DNA repair complex, the tumor suppressor p53, and DNA ligase IV. Here we show that the degradation of individual targets can occur independently of other substrates. Furthermore, we identify separation-of-function mutant forms of E1b55K that can distinguish substrates for binding and degradation. Our results identify distinct regions of E1b55K that are involved in substrate recognition but also imply that there are additional requirements beyond protein association. These mutant proteins will facilitate the determination of the relevance of specific substrates to the functions of E1b55K in promoting infection and inactivating host defenses.

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Manszewski, Tomasz, Kamil Szpotkowski e Mariusz Jaskolski. "Crystallographic and SAXS studies ofS-adenosyl-L-homocysteine hydrolase fromBradyrhizobium elkanii". IUCrJ 4, n. 3 (10 aprile 2017): 271–82. http://dx.doi.org/10.1107/s2052252517002433.

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S-Adenosyl-L-homocysteine hydrolase (SAHase) from the symbiotic bacteriumBradyrhizobium elkanii(BeSAHase) was crystallized in four ligand complexes with (i) mixed adenosine (Ado) and cordycepin (Cord; 3′-deoxyadenosine), (ii) adenine (Ade), (iii) Ado and (iv) mixed 2′-deoxyadenosine (2′-dAdo) and Ade. The crystal structures were solved at resolutions of 1.84, 1.95, 1.95 and 1.54 Å, respectively. Only the Ade complex crystallized with a dimer in the asymmetric unit, while all of the other complexes formed a crystallographically independent tetrameric assembly. In the Ado/Cord complex, adenosine is found in three subunits while the fourth subunit has cordycepin bound in the active site. In the Ade and Ado complexes only these ligand molecules are present in the active sites. The 2′-dAdo/Ade complex has Ade bound in two subunits and 2′-dAdo bound in the other two subunits. The BeSAHase fold adopted a closed conformation in the complexes with Ado, Ade and 2′-dAdo, and a semi-open conformation when cordycepin occupied the active site. An SAHase-specific molecular gate, consisting of residues His342 and Phe343, behaves differently in the different complexes, but there is no simple correlation with the ligand type. Additional small-angle X-ray scattering (SAXS) experiments confirm the tetrameric state of the protein in solution. The main conclusions from this work are (i) that the SAHase subunit does not simply oscillate between two discrete conformational open/closed states in correlation with the absence/presence of a ligand in the active site, but can also assume an intermediate form for some ligands; (ii) that the shut/open state of the molecular gate in the access channel to the active site is not correlated in a simple way with the open/closed subunit conformation or empty/occupied status of the active site, but that a variety of states are possible even for the same ligand; (iii) that a cation (typically sodium) coordinated in an intersubunit loop rigidifies a molecular hinge and thus stabilizes the closed conformation; (iv) that BeSAHase in solution is a tetramer, consistent with the model derived from crystallography.

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Grunebaum, Eyal, Andrea Bates e Chaim M. Roifman. "Omenn syndrome is associated with mutations in DNA ligase IV". Journal of Allergy and Clinical Immunology 122, n. 6 (dicembre 2008): 1219–20. http://dx.doi.org/10.1016/j.jaci.2008.08.031.

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Kim, V. H. D., E. Grunebaum, A. Bates e C. M. Roifman. "Omenn Syndrome is Associated with Mutations in DNA Ligase IV". Journal of Allergy and Clinical Immunology 123, n. 2 (febbraio 2009): S14. http://dx.doi.org/10.1016/j.jaci.2008.12.064.

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M. Naglah, Ahmed, Mohamed A. Al-Omar, Abdulrahman A. Almehizia, Ahmad J. Obaidullah, Mashooq A. Bhat, Atef Kalmouch, Asma S. Al-Wasidi, Jehan Y. Al-Humaidi e Moamen S. Refat. "Synthesis, Characterization, and Anti-diabetic Activity of Some Novel Vanadium-Folate-Amino Acid Materials". Biomolecules 10, n. 5 (18 maggio 2020): 781. http://dx.doi.org/10.3390/biom10050781.

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A new six intraperitoneal injections insulin-mimetic vanadyl(IV) compounds [(VO)(FA)(AAn)] (where n = 1–6: AA1 = isoleucine, AA2 = threonine, AA3 = proline, AA4 = phenylalanine, AA5 = lysine, and AA6 = glutamine) were synthesized by the chemical reactions between folic acid (FA), VOSO4, and amino acids (AAn) with equal molar ratio 1:1:1 in neutralized media. These complexes were characterized by elemental analysis and estimation of vanadyl(IV) metal ions. The thermal stability behavior of these complexes was studied by TG-DTG-DTA analyses. The structures of these complexes were elucidated by spectroscopic methods like infrared, electron spin resonance (ESR), and solid reflectance spectroscopes. The powder X-ray diffraction (XRD) study suggested the crystalline nature of the complexes. Magnetic moments and electronic spectra revealed the square-pyramid geometrical structure of the complexes. The conductivity results refereed that all synthesized vanadyl(IV) complexes were of a non-electrolyte behavior. The infrared spectra assignments of these complexes revealed that the FAH2 and AAn chelates act as a bidentate ligation. The chelation towards vanadyl (IV) ions existed via deprotonation of one of the carboxylic groups of FAH2 drug ligand, and so amino acids act as bidentate ligands via N-amino and O-carboxylate groups. Both scanning and transmission electron microscope (SEM and TEM) techniques were used to investigate the surface morphology. The main task of this research is the aim of designing a new insulin alternative antidiabetic drug agent. The antidiabetic efficiency of these complexes was evaluated in streptozotocin-induced diabetic male albino rats. Liver and kidney functions, insulin and blood glucose levels, lipid profile, and superoxide dismutase antioxidant (SOD) are verified identifiers for the efficiency of VO(IV)/FA/AAn system compounds as antidiabetic drug agents.

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Pan-Hammarström, Qiang, Anne-Marie Jones, Aleksi Lähdesmäki, Wei Zhou, Richard A. Gatti, Lennart Hammarström, Andrew R. Gennery e Michael R. Ehrenstein. "Impact of DNA ligase IV on nonhomologous end joining pathways during class switch recombination in human cells". Journal of Experimental Medicine 201, n. 2 (17 gennaio 2005): 189–94. http://dx.doi.org/10.1084/jem.20040772.

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Class switch recombination (CSR) is a region-specific, transcriptionally regulated, nonhomologous recombinational process that is initiated by activation-induced cytidine deaminase (AID). The initial lesions in the switch (S) regions are subsequently processed and resolved, leading to recombination of the two targeted S regions. The mechanisms by which repair and ligation of the broken DNA ends occurs is still elusive. Recently, a small number of patients lacking DNA ligase IV, a critical component of the nonhomologous end joining (NHEJ) machinery, have been identified. We show that these patients display a considerably increased donor/acceptor homology at Sμ–Sα junctions compared with healthy controls. In contrast, Sμ–Sγ junctions show an increased frequency of insertions but no increase in junctional homology. These altered patterns of junctional resolution may be related to differences in the homology between the Sμ and the downstream isotype S regions, and could reflect different modes of switch junction resolution when NHEJ is impaired. These findings link DNA ligase IV, and thus NHEJ, to CSR.

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Corazza, Fabio, Carlo Floriani, Angiola Chiesi-Villa e Carlo Guastini. "Titanium(IV) and zirconium(IV) tetrahydroborate moieties supported by a phenoxo ligand". Inorganic Chemistry 30, n. 1 (gennaio 1991): 145–48. http://dx.doi.org/10.1021/ic00001a028.

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Unal, Sule, Karen Cerosaletti, Duygu Uckan-Cetinkaya, Mualla Cetin e Fatma Gumruk. "A novel mutation in a family with DNA ligase IV deficiency syndrome". Pediatric Blood & Cancer 53, n. 3 (settembre 2009): 482–84. http://dx.doi.org/10.1002/pbc.22031.

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Jordan, Richard F. "Ligand redistribution reactions of dicyclopentadienylzirconium(IV) complexes". Journal of Organometallic Chemistry 294, n. 3 (ottobre 1985): 321–26. http://dx.doi.org/10.1016/0022-328x(85)87447-7.

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Bhargava, Sanieev, Rakesh Bohra e Ram C. Mehrotra. "Mixed ligand titanium(IV) complexes. Chlorobis(dithiocarbamato)bis(methylsalicylato)titanium(IV) andbis(dithiocarbamato)bis(methylsalicylato)titanium(IV)". Transition Metal Chemistry 16, n. 6 (dicembre 1991): 622–25. http://dx.doi.org/10.1007/bf01024201.

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Long, Gen, Kenneth Sabalo, Natalie MacDonald, Michael Beattie e Mostafa Sadoqi. "Photocurrent Enhancement by Introducing Gold Nanoparticles in Nanostructures Based Heterojunction Solar Cell Device". MRS Advances 2, n. 15 (2017): 817–24. http://dx.doi.org/10.1557/adv.2017.146.

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ABSTRACTIn this paper, we report a first hand study of plasmon-enhanced photocurrent observed in hybrid nanostructures based heterojunction solar cell. The heterojunction solar cell was fabricated, using chemically synthesized narrow gap, IV-VI group semiconductor nanoparticles (PbS) of 3∼6nm diameter, wide gap semiconductor ZnO nanowires of 500nm∼1 μm length and ∼50nm diameter, and gold nanoparticles (∼5nm to 30nm), by spin-coating (∼20cycles) onto FTO glasses, in ambient conditions (25°C, 1atm). The synthesized nanostructures were characterized by XRD, UV-VIS absorption, SEM, TEM, solar simulator, etc. Nanostructures of variant sizes were integrated in to the heterojunction devices to study the effects on photocurrent and solar cell performance. The sizes, lengths, thickness of nanostructures were optimized to have best solar cell devices. The effects of fabrication conditions (such as growth temperature, growth time, anneal temperature, ligand treatments, in air or in N2, etc.) on device performance were also studied. The architecture of film stack, i.e., the positions of Au nanoparticles and PbS nanoparticles were also studied. It was confirmed that introducing Au nanopartiles with proper size would lead to the increase of photocurrent. The key challenges were to minimize the trap states and optimize the interface of nanostructures.

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Zhan, Xiao-Yong, Jin-Lei Yang, Xuefu Zhou, Yi-Chao Qian, Ke Huang, Honghua Sun, Huacheng Wang, Yang Leng, Bihui Huang e Yulong He. "Virulence effector SidJ evolution in Legionella pneumophila is driven by positive selection and intragenic recombination". PeerJ 9 (17 agosto 2021): e12000. http://dx.doi.org/10.7717/peerj.12000.

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Effector proteins translocated by the Dot/Icm type IV secretion system determine the virulence of Legionella pneumophila (L. pneumophila). Among these effectors, members of the SidE family (SidEs) regulate several cellular processes through a unique phosphoribosyl ubiquitination mechanism mediated by another effector, SidJ. Host-cell calmodulin (CaM) activates SidJ to glutamylate the SidEs of ubiquitin (Ub) ligases and to make a balanced Ub ligase activity. Given the central role of SidJ in this regulatory process, studying the nature of evolution of sidJ is important to understand the virulence of L. pneumophila and the interaction between the bacteria and its hosts. By studying sidJ from a large number of L. pneumophila strains and using various molecular evolution algorithms, we demonstrated that intragenic recombination drove the evolution of sidJ and contributed to sidJ diversification. Additionally, we showed that four codons of sidJ which are located in the N-terminal (NTD) (codons 58 and 200) and C-terminal (CTD) (codons 868 and 869) domains, but not in the kinase domain (KD) had been subjected to strong positive selection pressure, and variable mutation profiles of these codons were identified. Protein structural modeling of SidJ provided possible explanations for these mutations. Codons 868 and 869 mutations might engage in regulating the interactions of SidJ with CaM through hydrogen bonds and affect the CaM docking to SidJ. Mutation in codon 58 of SidJ might affect the distribution of main-chain atoms that are associated with the interaction with CaM. In contrast, mutations in codon 200 might influence the α-helix stability in the NTD. These mutations might be important to balance Ub ligase activity for different L. pneumophila hosts. This study first reported that intragenic recombination and positive Darwinian selection both shaped the genetic plasticity of sidJ, contributing to a deeper understanding of the adaptive mechanisms of this intracellular bacterium to different hosts.

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Matsumoto, Kazuaki, Akihiro Hoshino, Akira Nishimura, Tamaki Kato, Yoshio Mori, Masaki Shimomura, Chie Naito et al. "DNA Ligase IV Deficiency Identified by Chance Following Vaccine-Derived Rubella Virus Infection". Journal of Clinical Immunology 40, n. 8 (10 settembre 2020): 1187–90. http://dx.doi.org/10.1007/s10875-020-00831-5.

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Smogorzewska, Agata, Jan Karlseder, Heidi Holtgreve-Grez, Anna Jauch e Titia de Lange. "DNA Ligase IV-Dependent NHEJ of Deprotected Mammalian Telomeres in G1 and G2". Current Biology 12, n. 19 (ottobre 2002): 1635–44. http://dx.doi.org/10.1016/s0960-9822(02)01179-x.

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Critchlow, Susan E., Richard P. Bowater e Stephen P. Jackson. "Mammalian DNA double-strand break repair protein XRCC4 interacts with DNA ligase IV". Current Biology 7, n. 8 (agosto 1997): 588–98. http://dx.doi.org/10.1016/s0960-9822(06)00258-2.

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Pandya, Bhavna J., e Pabitra K. Bhattacharya. "Mixed-ligand and binuclear complexes of oxovanadium(IV)". Transition Metal Chemistry 12, n. 4 (agosto 1987): 347–49. http://dx.doi.org/10.1007/bf01024031.

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Bursten, Bruce E., M. R. Green, V. Katovic, J. R. Kirk e D. Lightner. "Electrochemistry of niobium(IV) and tantalum(IV) complexes: ligand additivity in d1 octahedral complexes". Inorganic Chemistry 25, n. 6 (marzo 1986): 831–34. http://dx.doi.org/10.1021/ic00226a021.

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Majumdar, Amit, e Sabyasachi Sarkar. "Mixed-ligand tris chelated complexes of Mo(IV) and W(IV): A comparative study". Inorganica Chimica Acta 362, n. 10 (agosto 2009): 3493–501. http://dx.doi.org/10.1016/j.ica.2009.03.036.

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Buck, Dietke, Despina Moshous, Régina de Chasseval, Yunmei Ma, Françoise le Deist, Marina Cavazzana-Calvo, Alain Fischer, Jean-Laurent Casanova, Michael R Lieber e Jean-Pierre de Villartay. "Severe combined immunodeficiency and microcephaly in siblings with hypomorphic mutations in DNA ligase IV". European Journal of Immunology 36, n. 1 (gennaio 2006): 224–35. http://dx.doi.org/10.1002/eji.200535401.

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28

Andreev, Grigory, Nina Budantseva, Marina Sokolova e Aleksander Fedoseev. "Perrhenate and Pertechnetate Complexes of U(IV), Np(IV), and Pu(IV) with Dimethyl Sulfoxide as an O-Donor Ligand". Inorganic Chemistry 59, n. 16 (31 luglio 2020): 11357–65. http://dx.doi.org/10.1021/acs.inorgchem.0c01036.

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29

Schreiner, Sabrina, Peter Wimmer, Hüseyin Sirma, Roger D. Everett, Paola Blanchette, Peter Groitl e Thomas Dobner. "Proteasome-Dependent Degradation of Daxx by the Viral E1B-55K Protein in Human Adenovirus-Infected Cells". Journal of Virology 84, n. 14 (19 maggio 2010): 7029–38. http://dx.doi.org/10.1128/jvi.00074-10.

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ABSTRACT The death-associated protein Daxx found in PML (promyelocytic leukemia protein) nuclear bodies (PML-NBs) is involved in transcriptional regulation and cellular intrinsic antiviral resistence against incoming viruses. We found that knockdown of Daxx in a nontransformed human hepatocyte cell line using RNA interference (RNAi) techniques results in significantly increased adenoviral (Ad) replication, including enhanced viral mRNA synthesis and viral protein expression. This Daxx restriction imposed upon adenovirus growth is counteracted by early protein E1B-55K (early region 1B 55-kDa protein), a multifunctional regulator of cell-cycle-independent Ad5 replication. The viral protein binds to Daxx and induces its degradation through a proteasome-dependent pathway. We show that this process is independent of Ad E4orf6 (early region 4 open reading frame 6), known to promote the proteasomal degradation of cellular p53, Mre11, DNA ligase IV, and integrin α3 in combination with E1B-55K. These results illustrate the importance of the PML-NB-associated factor Daxx in virus growth restriction and suggest that E1B-55K antagonizes innate antiviral activities of Daxx and PML-NBs to stimulate viral replication at a posttranslational level.

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30

Yi, Qian-Feng Zhang, Tony C. H. Lam, Eddie Y. Y. Chan, Ian D. Williams e Wa-Hung Leung. "Phosphato, Chromato, and Perrhenato Complexes of Titanium(IV) and Zirconium(IV) Containing Kläui's Tripodal Ligand". Inorganic Chemistry 45, n. 1 (gennaio 2006): 328–35. http://dx.doi.org/10.1021/ic051329u.

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31

Deutscher, Jennifer, Philipp Gerschel, Katrin Warm, Uwe Kuhlmann, Stefan Mebs, Michael Haumann, Holger Dau, Peter Hildebrandt, Ulf-Peter Apfel e Kallol Ray. "A bioinspired oxoiron(iv) motif supported on a N2S2 macrocyclic ligand". Chemical Communications 57, n. 23 (2021): 2947–50. http://dx.doi.org/10.1039/d1cc00250c.

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A mononuclear oxoiron(iv) complex 1-trans bearing two equatorial sulfur ligations is synthesized and characterized as an active-site model of the elusive sulfur-ligated Fe^IVO intermediates in non-heme iron oxygenases.

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32

Basudhar, Pranab R., Sutapa Sinha, Pradyut K. Das e Barindra K. Ghosh. "Mixed-ligand complexes of osmium(III/IV)8-quinolinolates with one ketoximate ligand". Transition Metal Chemistry 21, n. 2 (aprile 1996): 154–57. http://dx.doi.org/10.1007/bf00136546.

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33

Chiruvella, Kishore K., Zhuobin Liang, Shanda R. Birkeland, Venkatesha Basrur e Thomas E. Wilson. "Saccharomyces cerevisiae DNA Ligase IV Supports Imprecise End Joining Independently of Its Catalytic Activity". PLoS Genetics 9, n. 6 (27 giugno 2013): e1003599. http://dx.doi.org/10.1371/journal.pgen.1003599.

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34

Nowak, Robert J., e Ronald D. Archer. "Tungsten(IV)/(V) eight-coordinate mixed-ligand-chelate electrochemistry". Inorganic Chemistry 25, n. 18 (agosto 1986): 3323–25. http://dx.doi.org/10.1021/ic00238a044.

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35

Lam, Tony C. H., Eddie Y. Y. Chan, Wing-Leung Mak, Samuel M. F. Lo, Ian D. Williams, Wing-Tak Wong e Wa-Hung Leung. "Half-Sandwich Titanium(IV) Complexes with Kläui's Tripod Ligand". Inorganic Chemistry 42, n. 6 (marzo 2003): 1842–47. http://dx.doi.org/10.1021/ic020287w.

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36

Filippou, Alexander C., e Sven Schneider. "Unusually Stable Chromium(IV) Alkyls Bearing a Triamidoamine Ligand". Organometallics 22, n. 15 (luglio 2003): 3010–12. http://dx.doi.org/10.1021/om030273d.

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37

Cheung, Wai-Man, Ho-Yuen Ng, Herman H. Y. Sung, Ian D. Williams e Wa-Hung Leung. "Dinuclear osmium(IV) oxo complexes with a dithioimidodiphosphinate ligand". Inorganica Chimica Acta 422 (ottobre 2014): 224–27. http://dx.doi.org/10.1016/j.ica.2014.05.030.

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38

Strand, Dagmar, Rolf Linder e Hans-Herbert Schmidtke. "The vibronic structure of mixed-ligand osmium(iv) complexes". Molecular Physics 71, n. 5 (10 dicembre 1990): 1075–89. http://dx.doi.org/10.1080/00268979000102331.

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39

Sonnenberger, David C., e John G. Gaudiello. "Cyclic voltammetric study of organoactinide compounds of uranium(IV) and neptunium(IV). Ligand effects on the M(IV)/M(III) couple". Inorganic Chemistry 27, n. 15 (luglio 1988): 2747–48. http://dx.doi.org/10.1021/ic00288a036.

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40

Bonatto, Diego, Martin Brendel e João Antonio Pêgas Henriques. "A new group of plant-specific ATP-dependent DNA ligases identified by protein phylogeny, hydrophobic cluster analysis and 3-dimensional modelling". Functional Plant Biology 32, n. 2 (2005): 161. http://dx.doi.org/10.1071/fp04143.

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Abstract (sommario):

The eukaryotic ATP-dependent DNA ligases comprise a group of orthologous proteins that have distinct roles in DNA metabolism. In contrast with the well-known DNA ligases of animal cells, the DNA ligases of plant cells are poorly described. Until now, only two DNA ligases (I and IV) genes of Arabidopsis thaliana (L.) Heynh were isolated and characterised. Use of the complete genomic sequences of Oryza sativa L. and A. thaliana, as well as the partially assembled genomic data of Medicago truncatula L. and Brassica spp., allowed us to identify a new family of ATP-dependent DNA ligases that are found only in the Viridiplantae kingdom. An in-depth phylogenetic analysis of protein sequences showed that this family composes a distinct clade, which shares a last universal common ancestor with DNA ligases I. In silico sequence studies indicate that these proteins have distinct physico-chemical properties when compared with those of animal and fungal DNA ligases. Moreover, hydrophobic cluster analysis and 3-dimensional modelling allowed us to map two conserved domains within these DNA ligases I-like proteins. Additional data of microsynteny analysis indicate that these DNA ligases I-like genes are linked to the S and SLL2 loci of Brassica spp. and A. thaliana, respectively. Combining the results of all analyses, we propose the creation of the DNA ligases VI (LIG6) family, which is composed by plant-specific DNA ligases.

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41

Bansod, Ashish, Ravindra Bhaskar, Chandarshekhar Ladole, Nilesh Salunkhe, Kanchan Thakare e Anand Aswar. "Mononuclear pyrazine-2-carbohydrazone metal complexes: Synthesis, structural assessment, thermal, biological, and electrical conductivity studies". European Journal of Chemistry 13, n. 1 (31 marzo 2022): 126–34. http://dx.doi.org/10.5155/eurjchem.13.1.126-134.2186.

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Mononuclear complexes of VO(IV), Cr(III), Fe(III), MoO2(VI), WO2(VI), and UO2(VI) with pyrazinecarbohydrazone ligand (N'-(1-(5-chloro-2-hydroxyphenyl)ethylidene)pyrazine-2-carbohydrazide) were synthesized and the prepared complexes were characterized by elemental analysis, magnetic susceptibility, powder X-ray analysis, various spectroscopic techniques (IR, 1H NMR, 13C NMR, and Mass spectra), SEM, and thermal analysis. VO(IV) complex was additionally characterized by ESR study. The ligand behaves as a dibasic tridentate, coordinating through the phenolate oxygen, azomethine nitrogen, and enolate oxygen atoms towards the central metal ion. The analytical data suggest 1:1 metal to ligand stoichiometry for all complexes. The physicochemical data suggested octahedral geometry to Cr(III), Fe(III), MoO2(VI), WO2(VI), and UO2(VI) complexes while square pyramidal to VO(IV) complex. The SEM analysis indicated the presence of well-defined crystals free from any shadow of the metal ion on their external surface with particle sizes of greater than 10 μm. Various kinetics and thermodynamic parameters are calculated using Coats-Redfern method and on the basis of half decomposition temperature the thermal stability order of complexes was found to be Cr(III) < WO2(VI) < Fe(III) < MoO2(VI) < VO(IV) < UO2(VI). The solid-state electrical conductivity of compounds was measured in their pellet form in the temperature range form 313-373 K. The conductivity data vary exponentially with the absolute temperature and obey Arrhenius equation indicating their semiconducting behavior. The antibacterial as well as antifungal activities of ligand and its metal complexes were evaluated in vitro against Gram positive bacteria (S. aureus and B. subtilis) and Gram-negative bacteria (E. coli and S. typhi.) and fungal strains (C. albicans and A. niger). The activity data revealed metal complexes are found to be more active than the ligand.

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42

Surbella, Robert G., Lucas C. Ducati, Jochen Autschbach, Kristi L. Pellegrini, Bruce K. McNamara, Jon M. Schwantes e Christopher L. Cahill. "Plutonium chlorido nitrato complexes: ligand competition and computational metrics for assembly and bonding". Chemical Communications 54, n. 85 (2018): 12014–17. http://dx.doi.org/10.1039/c8cc05578e.

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43

Hochegger, Helfrid, Donniphat Dejsuphong, Toru Fukushima, Ciaran Morrison, Eiichiro Sonoda, Valérie Schreiber, Guang Yu Zhao et al. "Parp-1 protects homologous recombination from interference by Ku and Ligase IV in vertebrate cells". EMBO Journal 25, n. 6 (23 febbraio 2006): 1305–14. http://dx.doi.org/10.1038/sj.emboj.7601015.

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44

Galligan, Leeona, Mark A. Catherwood, Treen C. Morris e H. Denis Alexander. "CD26 (Dipedtidyl Peptidase IV) Expression in B-CLL." Blood 110, n. 11 (16 novembre 2007): 4699. http://dx.doi.org/10.1182/blood.v110.11.4699.4699.

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Abstract Background CD26 (dipeptidyl peptidase IV) is a type II transmembrane glycoprotein with prolyl oligopeptidase activity and diverse biological functions including T-cell activation and chemokine regulation. The role of CD26 in tumour cell transformation and development is incompletely understood. Loss of CD26 expression has previously been associated with malignant transformation in melanoma. CD26 appears to be differentially expressed in T-cell malignancies and has been associated with reduced survival and shorter complete remissions in T-cell NHL. CD26 is also expressed on normal B-cells. However, the significance of its expression in malignant B-cell disorders remains unclear. Aims The aim of this study was to investigate the clinical and biological significance of membrane-associated CD26 expression in B-CLL. Methods Two hundred and thirty-two B-CLL patients were recruited for this study. Information on age at diagnosis, Binet clinical stage and time to treatment was available on all patients. Membrane expression of CD26 was assessed by 2-colour flow cytometric analysis of CD19 positive cells using anti CD26 PE. A value of ≥15% positivity was assigned to define a sub-group of patients (high CD26) with a relative increase in surface CD26 expression. IGHV mutational status and gene usage were determined using multiplex BIOMED-2 primers (InVivoScribe Technologies) and protocol and by sequence analysis. Interphase FISH analysis was performed to screen for common cytogenetic aberrations. Results A statistically significant increase in the proportion of males was detected in the high CD26 sub-group (80% versus 58.3% in the low CD26 sub-group, p<0.0001). In addition, increased CD26 expression was associated with advanced stage disease (31.6% versus 19.9%) requiring chemotherapeutic treatment (47.4% versus 29.1%). No association was observed between CD26 membrane expression and age at diagnosis nor with cytogenetic abnormalities commonly observed in B-CLL. However, somatic hypermutation of the IGVH gene was significantly more frequent in the low CD26 sub-group (p<0.0001). Preliminary results also indicate that IGVH 4–34 gene usage is associated with low CD26 membrane expression. In addition, IGHV 3–21 gene usage (n=19) was not detected in the high CD26 sub-group. Summary / Conclusions In our B-CLL cohort, increased CD26 B-cell membrane expression was associated with the male gender, un-mutated IGHV gene status and more advanced Binet stage requiring treatment, irrespective of age upon presentation. Interestingly, CD26 expression has previously been associated with unfavorable prognosis in T-cell malignancies and poor response to 2′-deoxycoformycin, an inhibitor of the CD26 ligand ADA, although there have been some reports of good responses in CD26 positive T-PLL. Furtheremore, CD26-positive hairy cell leukaemia responds favorably to 2′-deoxycoformycin treatment. The significance of CD26 expression in B-cell malignancies remains to be fully elucidated. The possibility that it may be linked to responsiveness to treatment with the ADA inhibitor 2′-deoxycoformycin is intriguing and warrants further investigation.

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45

Kapusta, Aurélie, Atsushi Matsuda, Antoine Marmignon, Michael Ku, Aude Silve, Eric Meyer, James D. Forney, Sophie Malinsky e Mireille Bétermier. "Highly Precise and Developmentally Programmed Genome Assembly in Paramecium Requires Ligase IV–Dependent End Joining". PLoS Genetics 7, n. 4 (14 aprile 2011): e1002049. http://dx.doi.org/10.1371/journal.pgen.1002049.

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46

Gómez-Ruiz, Santiago, Jesús Ceballos-Torres, Sanjiv Prashar, Mariano Fajardo, Željko Žižak, Zorica D. Juranić e Goran N. Kaluđerović. "One ligand different metal complexes: Biological studies of titanium(IV), tin(IV) and gallium(III) derivatives with the 2,6-dimethoxypyridine-3-carboxylato ligand". Journal of Organometallic Chemistry 696, n. 20 (ottobre 2011): 3206–13. http://dx.doi.org/10.1016/j.jorganchem.2011.06.036.

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47

Blackmore, Karen J., Joseph W. Ziller e Alan F. Heyduk. "“Oxidative Addition” to a Zirconium(IV) Redox-Active Ligand Complex". Inorganic Chemistry 44, n. 16 (agosto 2005): 5559–61. http://dx.doi.org/10.1021/ic050997c.

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48

Kutin, Yury, Nicholas Cox, Wolfgang Lubitz, Alexander Schnegg e Olaf Rüdiger. "In Situ EPR Characterization of a Cobalt Oxide Water Oxidation Catalyst at Neutral pH". Catalysts 9, n. 11 (6 novembre 2019): 926. http://dx.doi.org/10.3390/catal9110926.

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Abstract (sommario):

Here we report an in situ electron paramagnetic resonance (EPR) study of a low-cost, high-stability cobalt oxide electrodeposited material (Co-Pi) that oxidizes water at neutral pH and low over-potential, representing a promising system for future large-scale water splitting applications. Using CW X-band EPR we can follow the film formation from a Co(NO3)2 solution in phosphate buffer and quantify Co uptake into the catalytic film. As deposited, the film shows predominantly a Co(II) EPR signal, which converts into a Co(IV) signal as the electrode potential is increased. A purpose-built spectroelectrochemical cell allowed us to quantify the extent of Co(II) to Co(IV) conversion as a function of potential bias under operating conditions. Consistent with its role as an intermediate, Co(IV) is formed at potentials commensurate with electrocatalytic O2 evolution (+1.2 V, vs. SHE). The EPR resonance position of the Co(IV) species shifts to higher fields as the potential is increased above 1.2 V. Such a shift of the Co(IV) signal may be assigned to changes in the local Co structure, displaying a more distorted ligand field or more ligand radical character, suggesting it is this subset of sites that represents the catalytically ‘active’ component. The described spectroelectrochemical approach provides new information on catalyst function and reaction pathways of water oxidation.

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49

Bareš, Josef, Petr Novák, Milan Nádvorník, Roman Jambor, Tomáš Lébl, Ivana Císařová, Aleš Růžička e Jaroslav Holeček. "Monomeric Triorganotin(IV) Fluorides Containing a C,N-Chelating Ligand". Organometallics 23, n. 12 (giugno 2004): 2967–71. http://dx.doi.org/10.1021/om049912q.

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50

Leal, Joao Paulo, Noemia Marques, Antonio Pires de Matos, Maria J. Calhorda, Adelino M. Galvao e Jose A. Martinho Simoes. "Uranium-ligand bond dissociation enthalpies in uranium(IV) polypyrazolylborate complexes". Organometallics 11, n. 4 (aprile 1992): 1632–37. http://dx.doi.org/10.1021/om00040a038.

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