What is the trigger mechanism for the reversal of electron flow in oxygen-tolerant [NiFe] hydrogenases?

ABSTRACT: The [NiFe] hydrogenases use an electron transfer relay of three FeS clusters - proximal, medial and distal - to release the electrons from the principal reaction, H₂ → 2H⁺ + 2e^-, that occurs at the Ni-Fe catalytic site. This site is normally inactivated by O₂, but the subclass of O₂-tolerant [NiFe] hydrogenases are able to counter this inactivation through the agency of an unusual and unprecedented proximal cluster, with composition [Fe₄S₃(S^cys)₆], that is able to transfer two electrons back to the Ni-Fe site and effect crucial reduction of O₂-derived species and thereby reactivate the Ni-Fe site. This proximal cluster gates both the direction and the number of electrons flowing th

SUBMITTER: Dance I 

PROVIDER: S-EPMC5811149 | biostudies-literature | 2015 Feb

REPOSITORIES: biostudies-literature