Radical SAM Enzyme HydE Generates Adenosylated Fe(I) Intermediates En Route to the [FeFe]-Hydrogenase Catalytic H-Cluster.

ABSTRACT: The H-cluster of [FeFe]-hydrogenase consists of a [4Fe-4S]_H-subcluster linked by a cysteinyl bridge to a unique organometallic [2Fe]_H-subcluster assigned as the site of interconversion between protons and molecular hydrogen. This [2Fe]_H-subcluster is assembled by a set of Fe-S maturase enzymes HydG, HydE and HydF. Here we show that the HydG product [Fe^II(Cys)(CO)₂(CN)] synthon is the substrate of the radical SAM enzyme HydE, with the generated 5'-deoxyadenosyl radical attacking the cysteine S to form a C5'-S bond concomitant with reduction of the central low-spin Fe(II) to the Fe(I) oxidation state. This leads to the cleavage of the cysteine C3-S bond, producing a mononuclear [Fe^I(CO)₂(CN)S] species that serves as

SUBMITTER: Tao L 

PROVIDER: S-EPMC7440672 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature