Replacement of the axial copper ligand methionine with lysine in amicyanin converts it to a zinc-binding protein that no longer binds copper.

ABSTRACT: The mutation of the axial ligand of the type I copper protein amicyanin from Met to Lys results in a protein that is spectroscopically invisible and redox inactive. M98K amicyanin acts as a competitive inhibitor in the reaction of native amicyanin with methylamine dehydrogenase indicating that the M98K mutation has not affected the affinity for its natural electron donor. The crystal structure of M98K amicyanin reveals that its overall structure is very similar to native amicyanin but that the type I binding site is occupied by zinc. Anomalous difference Fourier maps calculated using the data collected around the absorption edges of copper and zinc confirm the presence of Zn(2+) at the type I site. The Lys98 NZ donates a hydrogen bond to a well-ordered water molecule at the type I site whi

SUBMITTER: Sukumar N 

PROVIDER: S-EPMC3233348 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature