(190af) Homology Modeling and Molecular Dynamics Simulations of a Bi-Directional Membrane Bound Hydrogenase From R. Eutropha H16

Homology modeling was used to create a three dimensional structure for the bi-directional membrane bound hydrogenase from R. eutropha. H16, which has not been solved using any method. The crystal structure was based on the membrane bound hydrogenase from A. Vinosum; the only crystallized membrane bound hydrogenase to date. The predicted structure of the hydrogenase contains two subunits, HoxK with three iron-sulfur centers, and HoxG which contains the nickel iron reaction center. HoxK appears to contain two distinct domains. The first is the iron-sulfur cluster containing domain, which is involved in the transportation of electrons to the reaction center. The second domain is not well defined in the homology model. However, molecular dynamics simulations were used to predict that this domain is a transmembrane alpha helix.  The predicted structures of the subunits of the hydrogenase agree reasonably well with experimentally determined structures, whit the exception of the C-terminal alpha helix on HoxK. This homology model will be later used in fusion models of hydrogenase from R. eutropha and photo system I from Thermosynechococcus elongates, to facilite the biological production of hydrogen.