Ca2+ binding sites in calmodulin and troponin C alter interhelical angle movements.
Molecular dynamics analyses were performed to examine conformational changes in the C-domain of calmodulin and the N-domain of troponin C induced by binding of Ca(2+) ions. Analyses of conformational changes in calmodulin and troponin C indicated that the shortening of the distance between Ca(2+) ions and Ca(2+) binding sites of helices caused widening of the distance between Ca(2+) binding sites of helices on opposite sides, while the hydrophobic side chains in the center of helices hardly moved due to their steric hindrance. This conformational change acts as the clothespin mechanism.
Goto
Kunihiko
K
Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School, 303 East Chicago Avenue, Chicago, IL 60611-3008, USA. kunihigoto@aol.com
Toyama
Akira
A
Takeuchi
Hideo
H
Takayama
Kazuyoshi
K
Saito
Tsutomu
T
Iwamoto
Masatoshi
M
Yeh
Jay Z
JZ
Narahashi
Toshio
T
D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000737:chemistry* / Q000378:metabolism; D003198:Computer Simulation; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008958:Models, Molecular; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D019209:Troponin C / Q000737:chemistry* / Q000378:metabolism; D029867:Xenopus Proteins / Q000737:chemistry / Q000378:metabolism
D002147:Calmodulin; D019209:Troponin C; D029867:Xenopus Proteins; D002118:Calcium