FIG 1.

Alignment of the Pa2KGDH amino acid sequence with those of known six-bladed quinoproteins. Perfect matches are boxed with a black background. Open boxes represent amino acid residues predicted to interact with PQQ via direct hydrogen bonding in known enzymes. The black arrowhead indicates the predicted catalytic histidine residue. Open arrowheads indicate conserved residues involved in PQQ binding in Pa2KGDH and known quinoproteins (27, 33, 34). 1CRU, glucose dehydrogenase from A. calcoaceticus; 3A9G, Asd from Pyrobaculum aerophilum; 3DAS, Asd from Streptomyces coelicolor; 2G8S, Asd from E. coli.