A Morphing [4Fe-3S-nO]-Cluster within a Carbon Monoxide Dehydrogenase Scaffold.

ABSTRACT: Ni,Fe-containing carbon monoxide dehydrogenases (CODHs) catalyze the reversible reduction of CO₂ to CO. Several anaerobic microorganisms encode multiple CODHs in their genome, of which some, despite being annotated as CODHs, lack a cysteine of the canonical binding motif for the active site Ni,Fe-cluster. Here, we report on the structure and reactivity of such a deviant enzyme, termed CooS-V_Ch . Its structure reveals the typical CODH scaffold, but contains an iron-sulfur-oxo hybrid-cluster. Although closely related to true CODHs, CooS-V_Ch catalyzes neither CO oxidation, nor CO₂ reduction. The active site of CooS-V_Ch undergoes a redox-dependent restructuring between a reduced [4Fe-3S]-cluster and an oxidized [4Fe-2S-S*-2O-2(H₂ O)]-cluster. Hydroxylamine, a slow-turnover substrate of CooS-V_Ch , oxidizes the hybrid-cluster in two structurally distinct steps. Overall, minor changes in CODHs are sufficient to accommodate a Fe/S/O-cluster in place of the Ni,Fe-heterocubane-cluster of CODHs.

SUBMITTER: Jeoung JH 

PROVIDER: S-EPMC9311411 | biostudies-literature | 2022 Apr

REPOSITORIES: biostudies-literature