Cofactor Assembly of Cytochrome bc 1 -b 6 f Complexes

Cline, Sara; Gabilly, Stéphane T.; Subrahmanian, Nitya; Hamel, Patrice

doi:10.1007/978-94-017-7481-9_26

Cited by 3 publications

(5 citation statements)

References 187 publications

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“…However, the functionality of laterally transferred cyt bc complexes in recipient cells would be limited by their ability to insert and covalently bind the c n heme. The incorporation of the c n heme in Chlamydomonas , plants and cyanobacteria requires a dedicated maturation system that operates from the n ‐side of the membrane (Kuras et al , de Vitry , Cline et al ). This system is absent in other prokaryotic groups that contain heme c n ; which systems are responsible for the insertion and covalent binding of heme c n in these organisms remains a mystery.…”

Section: Resultsmentioning

confidence: 99%

Emergence of cytochrome bc complexes in the context of photosynthesis

Dibrova

Shalaeva

Galperin

2017

Physiologia Plantarum

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The cytochrome bc (cyt bc) complexes are involved in Q‐cycling; they oxidize membrane quinols by high‐potential electron acceptors, such as cytochromes or plastocyanin, and generate transmembrane proton gradient. In several prokaryotic lineages, and also in plant chloroplasts, the catalytic core of the cyt bc complexes is built of a four‐helical cytochrome b (cyt b) that contains three hemes, a three‐helical subunit IV, and an iron‐sulfur Rieske protein (cytochrome b 6 f‐type complexes). In other prokaryotic lineages, and also in mitochondria, the cyt b subunit is fused with subunit IV, yielding a seven‐ or eight‐helical cyt b with only two hemes (cyt bc 1‐type complexes). Here we present an updated phylogenomic analysis of the cyt b subunits of cyt bc complexes. This analysis provides further support to our earlier suggestion that (1) the ancestral version of cyt bc complex contained a small four‐helical cyt b with three hemes similar to the plant cytochrome b 6 and (2) independent fusion events led to the formation of large cyts b in several lineages. In the search for a primordial function for the ancestral cyt bc complex, we address the intimate connection between the cyt bc complexes and photosynthesis. Indeed, the Q‐cycle turnover in the cyt bc complexes demands high‐potential electron acceptors. Before the Great Oxygenation Event, the biosphere had been highly reduced, so high‐potential electron acceptors could only be generated upon light‐driven charge separation. It appears that an ancestral cyt bc complex capable of Q‐cycling has emerged in conjunction with the (bacterio)chlorophyll‐based photosynthetic systems that continuously generated electron vacancies at the oxidized (bacterio)chlorophyll molecules.

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Section: Resultsmentioning

confidence: 99%

Emergence of cytochrome bc complexes in the context of photosynthesis

Dibrova

Shalaeva

Galperin

2017

Physiologia Plantarum

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“…No reuse allowed without permission. are deficient for cytochrome b 6 f assembly and photosynthesis (CLINE et al 2016; GABILLY AND HAMEL 2017).…”

Section: Introductionmentioning

confidence: 99%

“…Conversion of apocytochrome c to its corresponding holoform requires the formation of the thioether linkage(s) between the vinyl carbons in heme and the cysteine thiol(s) in the heme-binding motif. The chemical requirements for thioether bond formation were formulated from the in vitro reconstitution of holocytochrome c formation and the extensive genetic and biochemical dissection of cytochrome c maturation in bacterial and eukaryotic model systems (CLINE et al 2016; DAS AND HAMEL 2021) In energytransducing membranes, apo-to holocytochrome c conversion occurs on the p-side of the membrane and requires minimally: 1) the independent transport of apocytochrome c and heme substrates, 2) the chemical reduction of a) ferriheme to ferroheme and b) disulfide bonded hemelinking cysteines to free thiols, and 3) the stereospecific ligation of heme to the free thiols of the CXXCH motif via formation of thioether bond linkages. In vivo, heme ligation to CXXCH cysteine thiols is a catalyzed process requiring at least four different maturation systems (Systems I, II, III and IV) which are defined by signature assembly factors (MAVRIDOU et al 2013;TRAVAGLINI-ALLOCATELLI 2013;BABBITT et al 2015;GABILLY AND HAMEL 2017;BELBELAZI et al 2021).…”

Section: Introductionmentioning

confidence: 99%

“…Cytochrome f, one of the plastid c-type cytochromes, is a structural subunit of the cytochrome b 6 f complex and an essential electron carrier in photosynthesis, (KURAS AND WOLLMAN 1994;ZHOU et al 1996). Consequently, the ccs mutants are deficient for cytochrome b 6 f assembly and photosynthesis (CLINE et al 2016; GABILLY AND HAMEL 2017).…”

Section: Introductionmentioning

confidence: 99%

“…1996). Consequently, the ccs mutants are deficient for cytochrome b 6 f assembly and photosynthesis (C line et al . 2016; G abilly and H amel 2017).…”

Section: Introductionmentioning

confidence: 99%

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TWO DISULFIDE-REDUCING PATHWAYS ARE REQUIRED FOR THE MATURATION OF PLASTIDC-TYPE CYTOCHROMES INCHLAMYDOMONAS REINHARDTII

Das

Subrahmanian

Gabilly

et al. 2022

Preprint

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In plastids, conversion of light energy into ATP relies on cytochrome f, a key electron carrier with a heme covalently attached to a CXXCH motif. Covalent heme attachment requires reduction of the disulfide bonded CXXCH motif by CCS5 and CCS4, a protein of unknown function. CCS5 receives electrons from the oxido-reductase CCDA at the thylakoid membrane. In Chlamydomonas reinhardtii, loss of CCS4 or CCS5 function yields a partial cytochrome f assembly defect. Here we report that the Δccs4ccs5 double mutant displays a synthetic photosynthetic defect due to a complete loss of holocytochrome f assembly, a phenotype that can be chemically corrected by reducing agents. In Δccs4, the CCDA protein accumulation is decreased, indicating that one function of CCS4 is to stabilize CCDA. Dominant suppressor mutations mapping to the CCS4 gene were identified in photosynthetic revertants of the Δccs4ccs5 mutants. The suppressor mutations correspond to changes in the stroma-facing domain of CCS4 and restore holocytochrome f assembly above the residual levels detected in Δccs5. Because disulfide reduction via CCS5 no longer takes place in Δccs5, we hypothesize the suppressor mutations enhance the supply of reducing power independently of CCS5, uncovering the participation of CCS4 in a distinct redox pathway. CCS4-like proteins occur in the green lineage and are related to mitochondrial COX16, a protein involved in a disulfide reducing pathway. We discuss the operation of two pathways controlling the redox status of the heme-binding cysteines of apocytochrome f and the possible function of CCS4 as a shared component between the two pathways.

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Photosynthetic Proteins in Cyanobacteria: from Translocation to Assembly of Photosynthetic Complexes

Zedler

2024

Endosymbiotic Organelle Acquisition

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Cofactor Assembly of Cytochrome bc 1 -b 6 f Complexes

Cited by 3 publications

References 187 publications

Emergence of cytochrome bc complexes in the context of photosynthesis

Emergence of cytochrome bc complexes in the context of photosynthesis

TWO DISULFIDE-REDUCING PATHWAYS ARE REQUIRED FOR THE MATURATION OF PLASTIDC-TYPE CYTOCHROMES INCHLAMYDOMONAS REINHARDTII

Photosynthetic Proteins in Cyanobacteria: from Translocation to Assembly of Photosynthetic Complexes

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