Assembly of chloroplast cytochromes b and c

Nakamoto, Stacie S.; Hamel, Patrice; Merchant, Sabeeha

doi:10.1016/s0300-9084(00)00605-2

Cited by 33 publications

(53 citation statements)

References 93 publications

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“…As a control, we showed that the ccda mutations do not modify the expression of chloroplast petA and petB genes encoding apocytochrome f and apocytochrome b 6 , respectively (Fig. 5A).…”

Section: Ccda-1 -Tttatatacttgt--'--ttcaattatgttc-mentioning

confidence: 94%

“…Therefore, we chose to localize the in vitro synthesized radiolabeled protein after in vitro import into pea chloroplasts. We certainly expected CCDA to localize to chloroplasts based on the occurrence of the gene in the less derived red algal plastid genome of P. purpurea (6). Indeed, AtCCDA could be imported into isolated chloroplasts and was processed to the mature form, suggesting that the N-terminal extension functions as a chloroplast-targeting presequence in vitro (Fig.…”

Section: A Homolog Of Prokaryotic Thiol Disulfide Transportermentioning

confidence: 98%

“…CcdA in Photosynthetic Eukaryotes-We had noted the occurrence of a CcdA-encoding gene in the plastid genome of a rhodophyte alga, P. purpurea and also in the genomes of several cyanobacteria (6). With red algal CcdA as our prototype, we searched the nucleotide sequence data bases and identified expressed sequence tags corresponding to CcdA-like proteins from a number of photosynthetic eukaryotes, including Chlamydomonas, Arabidopsis, and several other vascular plants.…”

Section: A Homolog Of Prokaryotic Thiol Disulfide Transportermentioning

confidence: 99%

“…Mutations in CCDA Result in a Defect in Cytochrome b 6 f Complex Accumulation-We assessed the abundance of holocytochrome f in the mutant lines by heme staining and immunoblotting and also that of Rieske FeS, cytochrome b 6 , and subunit IV, which are subunits of the cytochrome b 6 f complex. As expected from the lack of phenotype in the ccda-2 and ccda-3 lines, holocytochrome f accumulation is not affected by these mutations, and the molecule assembles to essentially wild type level (Fig.…”

Section: Ccda-1 -Tttatatacttgt--'--ttcaattatgttc-mentioning

confidence: 99%

“…Loss-of-function of CcdA in bacteria results in a pleiotropic deficiency in c-type cytochromes, presumably because of a block in the reduction of apocytochrome c thiols in the heme binding site (24 -28). Interestingly, CcdA is physically linked to a gene encoding a homolog of Ccs1, a system II-specific cytochrome c biogenesis (19) in P. purpurea, Mycobacterium spp., and several cyanobacteria (6). This gene clustering speaks to a role for CcdA in the plastid cytochrome c maturation pathway, but no biochemical or genetic evidence is presently available to assign a function to the plant or cyanobacterial CcdAs.…”

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confidence: 99%

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A Homolog of Prokaryotic Thiol Disulfide Transporter CcdA Is Required for the Assembly of the Cytochrome bf Complex in Arabidopsis Chloroplasts

Page¹,

Hamel²,

Gabilly³

et al. 2004

Journal of Biological Chemistry

101

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The c-type cytochromes are defined by the occurrence of heme covalently linked to the polypeptide via thioether bonds between heme and the cysteine sulfhydryls in the CXXCH motif of apocytochrome. Maintenance of apocytochrome sulfhydryls in a reduced state is a prerequisite for covalent ligation of heme to the CXXCH motif. In bacteria, a thiol disulfide transporter and a thioredoxin are two components in a thio-reduction pathway involved in c-type cytochrome assembly. We have identified in photosynthetic eukaryotes nucleus-encoded homologs of a prokaryotic thiol disulfide transporter, CcdA, which all display an N-terminal extension with respect to their bacterial counterparts. The extension of Arabidopsis CCDA functions as a targeting sequence, suggesting a plastid site of action for CCDA in eukaryotes. Using PhoA and LacZ as topological reporters, we established that Arabidopsis CCDA is a polytopic protein with within-membrane strictly conserved cysteine residues. Insertional mutants in the Arabidopsis CCDA gene were identified, and loss-of-function alleles were shown to impair photosynthesis because of a defect in cytochrome b 6 f accumulation, which we attribute to a block in the maturation of holocytochrome f, whose heme binding domain resides in the thylakoid lumen. We postulate that plastid cytochrome c maturation requires CCDA, thioredoxin HCF164, and other molecules in a membrane-associated trans-thylakoid thiol-reducing pathway.The c-type cytochromes are a virtually ubiquitous yet rather structurally diverse group of hemoproteins that reside on the so-called p-side 1 of the energy-transducing membrane systems where they function typically as electron carriers (1, 2). The c-type cytochromes are defined by the occurrence of heme covalently attached to the polypeptide via two thioether linkages between the vinyl groups of heme and the cysteine sulfhydryls in the apocytochrome (1, 3). A CXXCH 2 sequence in the apocytochrome provides the thiols for formation of the thioether bonds, and the imidazole of the histidine residue serves as one of the axial ligands of the heme. Remarkably, three distinct assembly pathways, referred to as systems I, II, and III, have emerged through genetic analysis of c-type cytochrome maturation in bacteria, chloroplasts, and mitochondria (for review, see Refs. 1 and 4 -7), an unexpected finding for what appears on the surface to be a rather simple chemical reaction (i.e. the addition of apocytochrome cysteine thiols to the vinyls of heme). Each system can be distinguished on the basis of a sequence relationship of specific assembly factors. Yet, there is an underlying assumption that the three systems are united by common biochemical requirements for holocytochrome c biogenesis (for review, see Refs. 2, 4, and 8). For instance, the need for reducing conditions appears to be inherent to the chemistry of thioether bond formation (4). Both substrates, apocytochrome c sulfhydryls and heme, need to be maintained reduced prior to the ligation of heme as indicated from in vitro and in o...

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“…As a control, we showed that the ccda mutations do not modify the expression of chloroplast petA and petB genes encoding apocytochrome f and apocytochrome b 6 , respectively (Fig. 5A).…”

Section: Ccda-1 -Tttatatacttgt--'--ttcaattatgttc-mentioning

confidence: 94%

Section: A Homolog Of Prokaryotic Thiol Disulfide Transportermentioning

confidence: 98%

Section: A Homolog Of Prokaryotic Thiol Disulfide Transportermentioning

confidence: 99%

Section: Ccda-1 -Tttatatacttgt--'--ttcaattatgttc-mentioning

confidence: 99%

mentioning

confidence: 99%

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A Homolog of Prokaryotic Thiol Disulfide Transporter CcdA Is Required for the Assembly of the Cytochrome bf Complex in Arabidopsis Chloroplasts

Page¹,

Hamel²,

Gabilly³

et al. 2004

Journal of Biological Chemistry

101

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Cytochrome c assembly

2013

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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

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Thylakoid Biogenesis and Dynamics: The Result of a Complex Phylogenetic Puzzle

Herrmann

Westhoff

Regulation of Photosynthesis

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Assembly of chloroplast cytochromes b and c

Cited by 33 publications

References 93 publications

A Homolog of Prokaryotic Thiol Disulfide Transporter CcdA Is Required for the Assembly of the Cytochrome bf Complex in Arabidopsis Chloroplasts

A Homolog of Prokaryotic Thiol Disulfide Transporter CcdA Is Required for the Assembly of the Cytochrome bf Complex in Arabidopsis Chloroplasts

Cytochrome c assembly

Thylakoid Biogenesis and Dynamics: The Result of a Complex Phylogenetic Puzzle

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