2V4J

THE CRYSTAL STRUCTURE OF Desulfovibrio vulgaris DISSIMILATORY SULFITE REDUCTASE BOUND TO DsrC PROVIDES NOVEL INSIGHTS INTO THE MECHANISM OF SULFATE RESPIRATION

Summary for 2V4J

• Entry DOI: 10.2210/pdb2v4j/pdb
• Descriptor: SULFITE REDUCTASE, DISSIMILATORY-TYPE SUBUNIT ALPHA, SULFITE REDUCTASE, DISSIMILATORY-TYPE SUBUNIT BETA, SULFITE REDUCTASE, DISSIMILATORY-TYPE SUBUNIT GAMMA, ... (8 entities in total)
• Functional Keywords: dissimilatory sulfite reductase, siroheme, oxidoreductase, sirohydrochlorin
• Biological source: DESULFOVIBRIO VULGARIS; More
• Cellular location: Cytoplasm: P45573
• Total number of polymer chains: 6
• Total formula weight: 213776.79

Authors

Oliveira, T.F.,Vonrhein, C.,Matias, P.M.,Venceslau, S.S.,Pereira, I.A.C.,Archer, M. (deposition date: 2008-09-22, release date: 2008-12-02, Last modification date: 2024-10-23)

Primary citation

Oliveira, T.F.,Vonrhein, C.,Matias, P.M.,Venceslau, S.S.,Pereira, I.A.C.,Archer, M.
The Crystal Structure of Desulfovibrio Vulgaris Dissimilatory Sulfite Reductase Bound to Dsrc Provides Novel Insights Into the Mechanism of Sulfate Respiration.
J.Biol.Chem., 283:34141-, 2008

PubMed Abstract: Sulfate reduction is one of the earliest types of energy metabolism used by ancestral organisms to sustain life. Despite extensive studies, many questions remain about the way respiratory sulfate reduction is associated with energy conservation. A crucial enzyme in this process is the dissimilatory sulfite reductase (dSiR), which contains a unique siroheme-[4Fe4S] coupled cofactor. Here, we report the structure of desulfoviridin from Desulfovibrio vulgaris, in which the dSiR DsrAB (sulfite reductase) subunits are bound to the DsrC protein. The alpha(2)beta(2)gamma(2) assembly contains two siroheme-[4Fe4S] cofactors bound by DsrB, two sirohydrochlorins and two [4Fe4S] centers bound by DsrA, and another four [4Fe4S] centers in the ferredoxin domains. A sulfite molecule, coordinating the siroheme, is found at the active site. The DsrC protein is bound in a cleft between DsrA and DsrB with its conserved C-terminal cysteine reaching the distal side of the siroheme. We propose a novel mechanism for the process of sulfite reduction involving DsrAB, DsrC, and the DsrMKJOP membrane complex (a membrane complex with putative disulfide/thiol reductase activity), in which two of the six electrons for reduction of sulfite derive from the membrane quinone pool. These results show that DsrC is involved in sulfite reduction, which changes the mechanism of sulfate respiration. This has important implications for models used to date ancient sulfur metabolism based on sulfur isotope fractionations.

PubMed: 18829451
DOI: 10.1074/JBC.M805643200

Experimental method

X-RAY DIFFRACTION (2.1 Å)