Mechanism of calmodulin recognition of the binding domain of isoform 1b of the plasma membrane Ca(2+)-ATPase: kinetic pathway and effects of methionine oxidation.

ABSTRACT: Calmodulin (CaM) binds to a domain near the C-terminus of the plasma membrane Ca2+-ATPase (PMCA), causing the release of this domain and relief of its autoinhibitory function. We investigated the kinetics of dissociation and binding of Ca2+-CaM with a 28-residue peptide [C28W(1b)] corresponding to the CaM-binding domain of isoform 1b of PMCA. CaM was labeled with a fluorescent probe on either the N-terminal domain at residue 34 or the C-terminal domain at residue 110. Formation of complexes of CaM with C28W(1b) results in a decrease in the fluorescence yield of the fluorophore, allowing the kinetics of dissociation or binding to be detected. Using a maximum entropy method, we determined the minimum number and magnitudes of rate constants required to fit the data. Comparison of the fluoresc

SUBMITTER: Slaughter BD 

PROVIDER: S-EPMC2597417 | biostudies-literature | 2007 Apr

REPOSITORIES: biostudies-literature