A conserved motif liganding the [4Fe-4S] cluster in [4Fe-4S] fumarases prevents irreversible inactivation of the enzyme during hydrogen peroxide stress.

ABSTRACT: Organisms have evolved two different classes of the ubiquitous enzyme fumarase: the [4Fe-4S] cluster-containing class I enzymes are oxidant-sensitive, whereas the class II enzymes are iron-free and therefore oxidant-resistant. When hydrogen peroxide (H₂O₂) attacks the most-studied [4Fe-4S] fumarases, only the cluster is damaged, and thus the cell can rapidly repair the enzyme. However, this study shows that when elevated levels of H₂O₂ oxidized the class I fumarase of the obligate anaerobe Bacteroides thetaiotaomicron (Bt-Fum), a hydroxyl-like radical species was produced that caused irreversible covalent damage to the polypeptide. Unlike the fumarase of oxygen-tolerant bacteria, Bt-Fum lacks a key cysteine residue in the typical "CX_nC

SUBMITTER: Lu Z 

PROVIDER: S-EPMC6831887 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature