Proline 96 of the copper ligand loop of amicyanin regulates electron transfer from methylamine dehydrogenase by positioning other residues at the protein-protein interface.

ABSTRACT: Amicyanin is a type 1 copper protein that serves as an electron acceptor for methylamine dehydrogenase (MADH). The site of interaction with MADH is a "hydrophobic patch" of amino acid residues including those that comprise a "ligand loop" that provides three of the four copper ligands. Three prolines are present in this region. Pro94 of the ligand loop was previously shown to strongly influence the redox potential of amicyanin but not affinity for MADH or mechanism of electron transfer (ET). In this study Pro96 of the ligand loop was mutated. P96A and P96G mutations did not affect the spectroscopic or redox properties of amicyanin but increased the K(d) for complex formation with MADH and altered the kinetic mechanism for the interprotein ET reaction. Values of reorganization energy (λ) an

SUBMITTER: Choi M 

PROVIDER: S-EPMC3079385 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature