To explore the role of a cross-link between side chains of Tyr-288 and His-284 at the heme-copper binuclear center, we prepared cytochrome bo where d(4)-Tyr, 1-[(13)C]Tyr, or 4-[(13)C]Tyr has been biosynthetically incorporated. Unexpectedly, the d(4)-Tyr-labeled enzyme showed a large decrease in the ubiquinol-1 oxidase and CO binding activities. Optical absorption and resonance Raman spectra identified the defect in the distal side of the heme-copper binuclear center. In the CO-bound d(4)-Tyr-labeled enzyme, a large fraction of the nu((Fe-C)) mode was shifted from the normal 520-cm(-1) band to a broad band centered around 491 cm(-1), as found for the Y288F mutant. Our results suggested that the substitution of ring hydrogens of Tyr-288 with deuteriums slows down the formation of the His-Tyr cross-link essential for dioxygen reduction at the binuclear center.
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http://dx.doi.org/10.1074/jbc.M409719200 | DOI Listing |
Inorg Chem
January 2025
Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland.
Binuclear silver(I) and copper(I) complexes, and , with bridging diphenylphosphine ligands were prepared. In , the silver(I) center is located inside a trigonal plane composed of three phosphorus donors from three separate and bridging dppm ligands. The fourth coordination site is filled with neighboring silver(I) ions.
View Article and Find Full Text PDFMolecules
December 2024
High & New Technology Research Center of Henan Academy of Sciences, No. 56 Hongzhuan Road, Zhengzhou 450002, China.
A series of colorful binuclear Schiff bases derived from the different diamine bridges including 1,2- ethylenediamine (bis-Et-SA, bis-Et-4-NEt, bis-Et-5-NO, bis-Et-Naph), 1,2-phenylenediamine (bis-Ph-SA, bis-Ph-4-NEt, bis-Ph-5-NO, bis-Ph-Naph), dicyano-1,2-ethenediamine (bis-CN-SA, bis-CN-4-NEt, bis-CN-5-NO, bis-CN-Naph) have been designed and prepared. The optical properties of these binuclear Schiff base ligands were fully determined by UV-Vis absorption spectroscopy, fluorescence emission spectroscopy, and time-dependent-density functional theory (TD-DFT) calculations. The inclusion of D-A systems and/or π-extended systems in these binuclear Schiff base ligands not only enables adjustable RGB light absorption and emission spectra (300~700 nm) but also yields high fluorescence quantum efficiencies of up to 0.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Federal Research Centre "Fundamentals of Biotechnology", Russian Academy of Sciences, Moscow 119071, Russia.
The filamentous fungus (anamorph ) has been shown to be an efficient producer of secreted cellulases, used in biorefinery processes. Understanding the mechanisms of regulation of cellulase gene expression in the fungus is a current task in industrial biotechnology, since it allows for targeted changes in the composition of the complex secreted by the fungus. Expression of cellulase genes in fungi is regulated mainly at the level of transcription via pathway-specific transcription factors (TF), the majority of which belong to the Zn(II)2Cys6 family of zinc binuclear cluster proteins.
View Article and Find Full Text PDFACS Omega
December 2024
Departamento de Química, Instituto Tecnológico de Aeronáutica, São José dos Campos, São Paulo CEP 12228-900, Brazil.
The five-coordinate complex [RuCl(PNP)] () was synthesized from the binuclear [RuCl(-cym)] with a PNP-type ligand (PNP = 3,6-di--butyl-1,8-bis(dipropylphosphino)methyl)-9-carbazole - (Cbzdiphos )H) in a toluene solution, within 20 h at 110 °C, producing a green solid, which was precipitated with a 1/1 mixture of - pentane/HMDSO. The complex was characterized by NMR-H, C, and P{H}, mass spectroscopy-LIFDI, FTIR, UV/vis spectroscopy, and cyclic voltammetry, as well as a description of the optimized structure by DFT calculation. The reactivity of was investigated in the presence of potassium triethylborohydride (KBEtH, in THF solution of 1.
View Article and Find Full Text PDFEnviron Pollut
December 2024
Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China; Hubei Key Laboratory of Soil Environment and Pollution Remediation, College of Resources and Environment, Wuhan, 430070, China. Electronic address:
Organoarsenicals are toxic pollutants of global concern, and their environmental geochemical behavior might be greatly controlled by iron (Fe) (hydr)oxides through coprecipitation, which is rarely investigated. Here, the effects of the incorporation of dimethylarsenate (DMAs(V)), a typical organoarsenical, into the ferrihydrite (Fh) structure on the mineral physicochemical properties and Fe(II)-induced phase transformation of DMAs(V)-Fh coprecipitates with As/Fe molar ratios up to 0.0876 ± 0.
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