Cytochromes c biogenesis in a photosynthetic bacterium requires a periplasmic thioredoxin-like protein.

Beckman, Diana L.; Kranz, Robert G.

doi:10.1073/pnas.90.6.2179

Cited by 107 publications

(121 citation statements)

References 41 publications

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“…2, as are representative genera that possess each system. For systems I and II, there is a good understanding of how the CXXCH cysteines are reduced, using a general transmembrane thioredox protein such as DsbD (101) (or the smaller, related CcdA [43,139]) and dedicated thioredoxins such as CcsX (23) or CcmG (24). Figure 2 diagrams the thiol proteins (in red) which transfer reducing equivalents from inside the cell to outside.…”

Section: Cytochrome C Biogenesis: Three Systems and Some Emerging Spmentioning

confidence: 99%

CytochromecBiogenesis: Mechanisms for Covalent Modifications and Trafficking of Heme and for Heme-Iron Redox Control

Kranz¹,

Richard-Fogal²,

Taylor

et al. 2009

Microbiol Mol Biol Rev

223

372

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SUMMARY Heme is the prosthetic group for cytochromes, which are directly involved in oxidation/reduction reactions inside and outside the cell. Many cytochromes contain heme with covalent additions at one or both vinyl groups. These include farnesylation at one vinyl in hemes o and a and thioether linkages to each vinyl in cytochrome c (at CXXCH of the protein). Here we review the mechanisms for these covalent attachments, with emphasis on the three unique cytochrome c assembly pathways called systems I, II, and III. All proteins in system I (called Ccm proteins) and system II (Ccs proteins) are integral membrane proteins. Recent biochemical analyses suggest mechanisms for heme channeling to the outside, heme-iron redox control, and attachment to the CXXCH. For system II, the CcsB and CcsA proteins form a cytochrome c synthetase complex which specifically channels heme to an external heme binding domain; in this conserved tryptophan-rich “WWD domain” (in CcsA), the heme is maintained in the reduced state by two external histidines and then ligated to the CXXCH motif. In system I, a two-step process is described. Step 1 is the CcmABCD-mediated synthesis and release of oxidized holoCcmE (heme in the Fe+3 state). We describe how external histidines in CcmC are involved in heme attachment to CcmE, and the chemical mechanism to form oxidized holoCcmE is discussed. Step 2 includes the CcmFH-mediated reduction (to Fe+2) of holoCcmE and ligation of the heme to CXXCH. The evolutionary and ecological advantages for each system are discussed with respect to iron limitation and oxidizing environments.

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Section: Cytochrome C Biogenesis: Three Systems and Some Emerging Spmentioning

confidence: 99%

CytochromecBiogenesis: Mechanisms for Covalent Modifications and Trafficking of Heme and for Heme-Iron Redox Control

Kranz¹,

Richard-Fogal²,

Taylor

et al. 2009

Microbiol Mol Biol Rev

223

372

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“…However, by analogy with Rhodobacter capszrlatus and Bra4rhixobizrm japonicum, we would expect at least nine genes to be essential for the synthesis of cytochrome cL in addition to its structural gene, mxaG (Ramseier e t al., 1991;Beckman e t al., 1992;Ritz et al, 1993;Beckman & Kranz, 1993;Thonymeyer e t al., 1994a, b).…”

Section: Production Of Cytochrome Cmentioning

confidence: 99%

“…The haem-binding site (Cys-X-XCys-His) of the cytochrome c must be reduced before haem attachment can take place and a thioredoxin-like protein is probably required for this (Beckman & Kranz, 1993 ; Thonymeyer e t al.,…”

mentioning

confidence: 99%

The biosynthesis of periplasmic electron transport proteins in methylotrophic bacteria

Goodwin

Anthony

1995

Microbiology

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“…A plausible current model is that the two cysteine residues in the CXXCH motif of a polypeptide destined to become a c-type cytochrome are oxidized to a disulfide bridge before re-reduction linked to the attachment of the haem (Metheringham et al, 1995 ;Sambongi & Ferguson, 1996). This re-reduction is proposed to involve DipZ, either directly or as a donor of reducing power to a periplasmic thioredoxin-like protein, CcmG (Sambongi & Ferguson, 1994;, which is specifically required for periplasmic c-type cytochrome biogenesis (Beckman & Kranz, 1993;Thony-Meyer et al, 1995). Whereas the first E. coli mutant found to be pleiotropically deficient in c-type cytochromes was mutated in d i p z , it is very striking that this gene has never been found in screens for c-type cytochrome deficiency in several other organisms including Rhodobacter capsulatus, Paracoccus denitrificans and Bradyrhizobium japonicum.…”

Section: D Page N F W S a U N D E R S A N D S J F E R G U mentioning

confidence: 99%

Disruption of the Pseudomonas aeruginosa dipZ gene, encoding a putative protein-disulfide reductase, leads to partial pleiotropic deficiency in c-type cytochrome biogenesis

1997

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The Pseudomonas eenrginou) dip2 gene has been cloned and sequenced. Whereas disruption of Escherichie COIi dip2 (dolbD), the hydrophilic C-terminal domain of which has been deduced to be periplasmic and to function as a protein-disulfide reductase, leads to the absence of c-type cytochromes, disruption of P. aenrginou) dip2 attenuated, but did not abolish, holo-c-type cytochrome biosynthesis. Comparison of the P. aenrginosa DipZ sequence with three other DipZ sequences indicated that there are not only two conserved cysteine residues in the C-terminal hydrophilie domain, but also two more in the central highly hydrophobic domain. The latter would be located toward the centre of two of the eight membrane-spanning oc-helices predicted t o compose the hydrophobic central domain of DipZ. Both these cysteine residues, plus other transmembrane helix residues, notably prolines and glycines, are also conserved in a t ( w p of membrane proteins, related t o Bacillus subtilis CcdA, which lack the N-and C-terminal hydrophilic domains of the DipZ proteins. It is proposed that Dip2 of P. eenrginosa and other organisms transfers reducing power from the cytoplasm t o the periplasm through reduction and reoxidation of an intramembrane disulf ide bond, or other mechanism involving these cysteine residues, and that this function can also be performed by B. subtoltr CcdA and other CcdA-like proteins. The failure of dip2 disruption to abolish etype cytochrome synthesis in P. eenrginosa suggests that, in contrast to the situation in E. d i , the absence of DipZ can be compensated for by one or more other proteins, for example a CcdA-like protein acting in tandem with one or more thioredoxin-like proteins.

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Cytochromes c biogenesis in a photosynthetic bacterium requires a periplasmic thioredoxin-like protein.

Abstract: Rhodobacter capsulatus is a

Cited by 107 publications

References 41 publications

CytochromecBiogenesis: Mechanisms for Covalent Modifications and Trafficking of Heme and for Heme-Iron Redox Control

CytochromecBiogenesis: Mechanisms for Covalent Modifications and Trafficking of Heme and for Heme-Iron Redox Control

The biosynthesis of periplasmic electron transport proteins in methylotrophic bacteria

Disruption of the Pseudomonas aeruginosa dipZ gene, encoding a putative protein-disulfide reductase, leads to partial pleiotropic deficiency in c-type cytochrome biogenesis

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