Fig. 1. (A) Sequence alignment showing the conservation of large subunit residue 73 amongst oxygen tolerant and oxygen sensitive NiFe hydrogenases. Ec = E. coli; Se = Salmonella enterica; Re = Ralstonia eutropha; Ae = Aquifex aeolicus; Av = Allochromatium vinosum; Dg = Desulfovibrio gigas; Dv = Desulfovibrio vulgaris; Db = Desulfomicrobium baculatum. (B) Crystal structures of (i) an oxygen tolerant MBH (PDB: ; 3RGW) and (ii) an oxygen sensitive NiFe hydrogenase (PDB: ; 4UD2), showing the location of residue 73 relative to the active site and the proximal cluster. The H-bonding capacity of residue 73 is denoted by the dashed black lines. E. coli numbering is used throughout.
