6ons | pdb_00006ons

Crystal structure of Desulfovibrio vulgaris carbon monoxide dehydrogenase with the D-cluster ligating cysteines mutated to alanines, coexpressed with CooC, as-isolated

spinqualitylabelsall models 6ons, resolution 2.48Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6ons is a 1 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: SF4, XCC Related: 6ond, 6onc Activity: Anaerobic carbon-monoxide dehydrogenase, with EC number 1.2.7.4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed The nickel-dependent carbon monoxide dehydrogenase (CODH) employs a unique heterometallic Ni-Fe-S cluster, termed the Ccluster, to catalyze the interconversion of CO and CO2 Like other complex metalloenzymes, CODH requires dedicated assembly machinery to form the fully intact and functional C-cluster. In particular, nickel incorporation into the C-cluster depends on the maturation factor CooC; however, the mechanism of nickel insertion remains poorly understood. Here, we compare X-ray structures (1.50-2.48 A resolution) of CODH from Desulfovibrio vulgaris (DvCODH) heterologously expressed in either the absence (DvCODH(-CooC)) or presence (DvCODH(+CooC)) of co-expressed CooC. We find that the C-cluster of DvCODH(-CooC) is fully loaded with iron but does not contain any nickel. Interestingly, the so-called unique iron ion (Feu) occupies both its canonical site (80% occupancy) and the nickel site (20% occupancy), with addition of reductant causing further mismetallation of the nickel site (60% iron occupancy). We also demonstrate that a DvCODH variant that lacks a surface-accessible Fe-S cluster (the D-cluster) has a C-cluster that is also replete in iron but lacks nickel, despite co-expression with CooC. In this variant, all Feu is in its canonical location and the nickel site is empty. This Dcluster-deficient CODH is inactive despite attempts to reconstitute it with nickel. Taken together, these results suggest that an empty nickel site is not sufficient for nickel incorporation. Based on our findings, we propose a model for Ccluster assembly that requires both CooC and a functioning D-cluster, involves precise redox-state control, and includes a two-step nickel-binding process. Structural insight into metallocofactor maturation in carbon monoxide dehydrogenase.,Wittenborn EC, Cohen SE, Merrouch M, Leger C, Fourmond V, Dementin S, Drennan CL J Biol Chem. 2019 Jul 11. pii: RA119.009610. doi: 10.1074/jbc.RA119.009610. PMID:31296570 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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