C-type cytochromes with histidine-methionine (His-Met) iron coordination play important roles in electron-transfer reactions and in enzymes. Low-temperature electron paramagnetic resonance (EPR) spectra of low-spin ferric cytochromes c can be divided into two groups, depending on the spread of g values: the normal rhombic ones with small g anisotropy and g(max) below 3.2, and those featuring large g anisotropy with g(max) between 3.3 and 3.8, also denoted as highly axial low spin (HALS) species. Herein we present the detailed magnetic properties of cytochrome c(553) from Bacillus pasteurii (g(max) 3.36) and cytochrome c(552) from Nitrosomonas europaea (g(max) 3.34) over the pH range 6.2 to 8.2. Besides being structurally very similar, cytochrome c(553) shows the presence of a minor rhombic species at pH 6.2 (6 %), whereas cytochrome c(552) has about 25 % rhombic species over pH 7.5. The detailed Mössbauer analysis of cytochrome c(552) confirms the presence of these two low-spin ferric species (HALS and rhombic) together with an 8 % ferrous form with parameters comparable to the horse cytochrome c. Both EPR and Mössbauer data of axial cytochromes c with His-Met iron coordination are consistent with an electronic (d(xy))(2) (d(xz))(2) (d(yz))(1) ground state, which is typical for Type I model hemes.
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http://dx.doi.org/10.1002/cphc.200500693 | DOI Listing |
PLoS One
November 2023
Faculty of Science, Chemistry Department, Islamic University of Madinah, Al-Madinah Al-Munawarah, Saudi Arabia.
Cytochrome c552 from Thermus thermophilus is one of the hot topics for creating smart biomaterials as it possesses remarkable stability, is tolerant to multiple mutations and has therefore been recently reported for a number of functionalizations upon substitution of the original prosthetic group with an artificial prosthetic group. However, all of the substitutions were driven by the coordination through the axial ligands followed by complete reconstitution with a metal-porphyrin complex. This limits the scope of the cytochrome c for incorporating a metal-less non-natural heme species that could improve the versatility of cytochrome c for a new generation of engineered cytochrome proteins for further enhancement in their functionalities such as biocatalysts.
View Article and Find Full Text PDFActa Crystallogr D Struct Biol
April 2023
School of Chemistry and The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Australia.
The arsenite oxidase (AioAB) from Pseudorhizobium banfieldiae sp. strain NT-26 catalyzes the oxidation of arsenite to arsenate and transfers electrons to its cognate electron acceptor cytochrome c (cytc). This activity underpins the ability of this organism to respire using arsenite present in contaminated environments.
View Article and Find Full Text PDFBiomolecules
September 2022
Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan.
A cytochrome mutant from HB8 ( C14A) was reported, where the polypeptide with replaced Cys14 by alanine, overexpressed in the cytosol of . The apo-form of the C14A mutant (apo-C14A) without the original prosthetic group was obtained by simple chemical treatments that retained compact conformation amenable to reconstitution with heme and zinc(II)-protoporphyrin(IX), gradually followed by spontaneous formation of a covalent bond between the polypeptide and porphyrin ring in the reconstituted apo-C14A. Further analysis suggested that the residual Cys11 and vinyl group of the porphyrin ring linked through the thiol-ene reaction promoted by light under ambient conditions.
View Article and Find Full Text PDFInt J Mol Sci
September 2022
Bach Institute of Biochemistry, Federal Research Center "Fundamentals of Biotechnology", Russian Academy of Sciences, Moscow 119071, Russia.
The search of a putative physiological electron acceptor for thiocyanate dehydrogenase (TcDH) newly discovered in the thiocyanate-oxidizing bacteria revealed an unusually large, single-heme cytochrome (CytC552), which was co-purified with TcDH from the periplasm. Recombinant CytC552, produced in as a mature protein without a signal peptide, has spectral properties similar to the endogenous protein and serves as an in vitro electron acceptor in the TcDH-catalyzed reaction. The CytC552 structure determined by NMR spectroscopy reveals significant differences compared to those of the typical class I bacterial cytochromes : a high solvent accessible surface area for the heme group and so-called "intrinsically disordered" nature of the histidine-rich N- and C-terminal regions.
View Article and Find Full Text PDFJ Microbiol
May 2022
Department of Biology, Faculty of Sciences, University of Zanjan, Zanjan, 45371-38791, Iran.
Cyc (Cytochrome c) is a protein in the electron transport chain of the Acidithiobacillus ferrooxidans (Af) bacteria which obtain their energy from oxidation Fe to Fe. The electrons are directed through Cyc, RCY (rusticyanin), Cyc and Cox aa proteins to O. Cyc protein consists of two chains, A and B.
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