Ca(2+) dissociation from the C-terminal EF-hand pair in calmodulin: a steered molecular dynamics study.
We used steered molecular dynamics (SMD) to simulate the process of Ca(2+) dissociation from the EF-hand motifs of the C-terminal lobe of calmodulin. Based on an analysis of the pulling forces, the dissociation sequences and the structural changes, we show that the Ca(2+)-coordinating residues lose their binding to Ca(2+) in a stepwise fashion. The two Ca(2+) ions dissociate from the two EF-hands simultaneously, with two distinct groups among the five Ca(2+)-coordinating residues affecting the EF-hand conformational changes differently. These results provide new insights into the effects of Ca(2+) on calmodulin conformation, from which a novel sequential mechanism of Ca(2+)-calmodulin dissociation is proposed.
Zhang
Yong
Y
Department of Chemistry, Beijing Normal University, Beijing 100875, People's Republic of China.
Tan
Hongwei
H
Lu
Yanyan
Y
Jia
Zongchao
Z
Chen
Guangju
G
D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000737:chemistry / Q000378:metabolism*; D020832:EF Hand Motifs; D008958:Models, Molecular; D011487:Protein Conformation
D002147:Calmodulin; D002118:Calcium