Interaction Between Putidaredoxin and Its Redox Partner, Putidaredoxin Reductase
Marcia J. Holden, M P. Mayhew, V L. Vilker
Using site-directed mutagenesis we altered surface residues on Putidaredoxin to investigate which side-chain residues might be involved in the binding of Putidaredoxin to its redox partner, Putidaredoxin reductase. We focused on the charged residues of helix G as a potential target site due to the significant homologies of Putidaredoxin with adrenodoxin and the well-defined role that the analoxous helix F plays in the interaction of adrenodoxin with adrenodoxin reductase. This region was also the study target of Aoki and coworkers who were successful in studying two of the helix glutamate residues and a third in the region [M. Aoki Biochim. Biophys. Acta 1386: 157, 1998; M Aoki et al. Inorgan. Chim. Acta 272:80, 1998]'. We conducted similar studies on those three as well as two others. Our data is in agreement with that of Aoki on residues Glu 65, Glu 72 and Glu 77. Our new data on Glu 65 and ARg 66 shed some new light on Pdx-PdR interactions.