Conserved Histidine Adjacent to the Proximal Cluster Tunes the Anaerobic Reductive Activation of Escherichia coli Membrane-Bound [NiFe] Hydrogenase-1.

ABSTRACT: [NiFe] hydrogenases are electrocatalysts that oxidize H₂ at a rapid rate without the need for precious metals. All membrane-bound [NiFe] hydrogenases (MBH) possess a histidine residue that points to the electron-transfer iron sulfur cluster closest ("proximal") to the [NiFe] H₂-binding active site. Replacement of this amino acid with alanine induces O₂ sensitivity, and this has been attributed to the role of the histidine in enabling the reversible O₂-induced over-oxidation of the [Fe₄S₃Cys₂] proximal cluster possessed by all O₂-tolerant MBH. We have created an Escherichia coli Hyd-1 His-to-Ala variant and report O₂-free electrochemical measurements at high potential that indicate the

SUBMITTER: Flanagan LA 

PROVIDER: S-EPMC5900901 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature