Cytochrome c assembly

Abstract

Cytochromes c are central proteins in energy transduction processes by virtue of their functions in electron transfer in respiration and photosynthesis. They have heme covalently attached to a characteristic CXXCH motif via protein-catalyzed post-translational modification reactions. Several systems with diverse constituent proteins have been identified in different organisms and are required to perform the heme attachment and associated functions. The necessary steps are translocation of the apocytochrome polypeptide to the site of heme attachment, transport and provision of heme to the appropriate compartment, reduction and chaperoning of the apocytochrome, and finally, formation of the thioether bonds between heme and two cysteines in the cytochrome. Here we summarize the established classical models for these processes and present recent progress in our understanding of the individual steps within the different cytochrome c biogenesis systems. V C 2013 IUBMB Life, 65(3): [209][210][211][212][213][214][215][216] 2013

Deciphering protein–protein interactions during the biogenesis of cytochrome c oxidase from Paracoccus denitrificans

“…A variety of chaperones have previously been confirmed to be involved in the transport of heme across the membrane and its incorporation into cytochrome c [34]. CcmE, a unique heme chaperone that covalently binds heme b before transferring it to apocytochrome c, and CcmF, a factor that releases the heme attached to CcmE [35,36], were detected in elution fractions obtained from solubilized membranes of untreated cells when anti-COX (N or D) was used as the bait antibody ( Table 1). The presence of these two factors along with CtaB invites speculation as to their role in the process of heme a biosynthesis; moreover, MS analysis of the cross-linked samples revealed the presence of CcmE, CcmF, CcsA (CcmC), CcmG and CcdA [37,38] in all the elution fractions using bait antibodies (Tables S3 and S4).…”

NO2−-mediated nitrosylation of ferrous microperoxidase-11

“…The prosthetic group of cyt c is formed from the condensation of heme b with two protein Cys residues via thioether bonds. The fifth coordination ligand of the heme-Fe atom of cyt c is invariantly His, whereas the sixth coordination ligand exhibits high variability, being Met in horse heart cyt c [1][2][3][4][5][6][7]. The heme-Fe atom of hexa-coordinated native horse heart cyt c is essentially unreactive (or very low reactive), whereas the heme-Fe atom of penta-coordinated cyt c derivatives (i.e., carboxymethylated cyt c (CM-cyt c), cardiolipinbound CM-cyt c (CL-CM-cyt c), and cardiolipin-bound cyt c (CL-cyt c)) displays myoglobin-like spectroscopic and functional properties [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21].…”

“…MP11 is a heme-peptide complex formed by eleven amino acid residues (i.e., Val11-Gln12-Lys13-Cys14-Ala15-Gln16-Cys17-His18-Thr19-Val20-Glu21) and a heme c covalently-linked to the Cys-Xxx-Xxx-CysHis sequence, which is highly conserved within most cyt c (Fig. 1) [1][2][3][4][5][6]22]. MP11 is penta-coordinated (i.e., ligand-free) in the ferrous form ( Fig.…”

Evaluative Profiling of Arsenic Sensing and Regulatory Systems in the Human Microbiome Project Genomes

“…For example, in multiple Bacteroides genomes, a gene for arsenic binding and transfer (arsD) is adjacent to a gene for cytochrome c biogenesis protein. Cytochrome c , produced by a posttranslational process, consists of heme-containing proteins important for cellular energy production and signaling 28,29. Previous reported research on Bacteroides and arsenic appears to be limited to phenotypic characterization of susceptibilities to arsenate in which 25% of strains in the Bacteroides fragilis group, which included Bacteroides thetaiotaomicron , were resistant to 0.01 M arsenate 30.…”