Calmodulin in complex with the first IQ motif of myosin-5a functions as an intact calcium sensor.

ABSTRACT: The motor function of vertebrate myosin-5a is inhibited by its tail in a Ca²⁺-dependent manner. We previously demonstrated that the calmodulin (CaM) bound to the first isoleucine-glutamine (IQ) motif (IQ1) of myosin-5a is responsible for the Ca²⁺-dependent regulation of myosin-5a. We have solved the crystal structure of a truncated myosin-5a containing the motor domain and IQ1 (MD-IQ1) complexed with Ca²⁺-bound CaM (Ca²⁺-CaM) at 2.5-Å resolution. Compared with the structure of the MD-IQ1 complexed with essential light chain (an equivalent of apo-CaM), MD-IQ1/Ca²⁺-CaM displays large conformational differences in IQ1/CaM and little difference in the motor domain. In the MD-IQ1/Ca²⁺-CaM structure, the N-lobe and the C-lobe of C

SUBMITTER: Shen M 

PROVIDER: S-EPMC5056106 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature