Figure 5
Schematic diagram of H 2 production by the co-expression of proteorhodopsin and [NiFe]-hydrogenase in E. coli. Proteorhodopsin transports protons across the membrane by absorption of light energy. Protons are transferred to the active site in the large subunit (L) of [NiFe]-hydrogenase in the periplasm and reduced to H2 by the addition of an electron, which is transferred thorough [Fe-S] clusters in the small subunit of [NiFe]-hydrogenase (S) and b-type cytochrome (Cyt b, encoded by hyaC in E. coli) in the inner membrane. Abbreviations: OM, outer membrane; PS, periplasmic space; IM, inner membrane.