Paramagnetic Cu(II) for probing membrane protein structure and function: inhibition mechanism of the influenza M2 proton channel.

ABSTRACT: Paramagnetic Cu(II) ions enhance nuclear spin relaxation in a distance-dependent fashion and can be used as a structural probe of proteins. Cu(II) can also serve as a functionally important ligand in proteins. Here we investigate the structural basis of Cu(II) inhibition of the influenza M2 proton channel through Cu(II)-induced paramagnetic relaxation enhancement (PRE). (13)C T(1) relaxation rates of the central residues of the transmembrane (TM) domain of M2 are significantly enhanced by Cu(II), and pronounced spectral broadening is observed for the proton-selective residue, His37. These data yielded quantitative distances of (13)C spins to the Cu(II) center and identified the Cu(II) binding site to be Nε2 of His37. This binding site is surrounded by four imidazole rings from the top and

SUBMITTER: Su Y 

PROVIDER: S-EPMC3465501 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature