Download MendeleyHis-Ligation to the [4Fe-4S] Subcluster Tunes the Catalytic Bias of [FeFe] Hydrogenase.
Rodriguez-Macia, P., Kertess, L., Burnik, J., Birrell, J.A., Hofmann, E., Lubitz, W., Happe, T., Rudiger, O.(2019) J Am Chem Soc 141: 472-481
- PubMed: 30545220
- DOI: https://doi.org/10.1021/jacs.8b11149
- Primary Citation of Related Structures:
6GL6 - PubMed Abstract:
[FeFe] hydrogenases interconvert H 2 into protons and electrons reversibly and efficiently. The active site H-cluster is composed of two sites: a unique [2Fe] subcluster ([2Fe] H ) covalently linked via cysteine to a canonical [4Fe-4S] cluster ([4Fe-4S] H ). Both sites are redox active and electron transfer is proton-coupled, such that the potential of the H-cluster lies very close to the H 2 thermodynamic potential, which confers the enzyme with the ability to operate quickly in both directions without energy losses. Here, one of the cysteines coordinating [4Fe-4S] H (Cys362) in the [FeFe] hydrogenase from the green algae Chlamydomonas reinhardtii ( CrHydA1) was exchanged with histidine and the resulting C362H variant was shown to contain a [4Fe-4S] cluster with a more positive redox potential than the wild-type. The change in the [4Fe-4S] cluster potential resulted in a shift of the catalytic bias, diminishing the H 2 production activity but giving significantly higher H 2 oxidation activity, albeit with a 200 mV overpotential requirement. These results highlight the importance of the [4Fe-4S] cluster as an electron injection site, modulating the redox potential and the catalytic properties of the H-cluster.
Organizational Affiliation:
Max Planck Institute for Chemical Energy Conversion , Stiftstraße 34-36 , 45470 Mülheim an der Ruhr , Germany.
