title: Ca2+ binding sites in calmodulin and troponin C alter interhelical angle movements.
abstract: 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.
authors.affiliation: Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School, 303 East Chicago Avenue, Chicago, IL 60611-3008, USA. kunihigoto@aol.com
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Goto
authors.forename: Akira
authors.initials: A
authors.lastname: Toyama
authors.forename: Hideo
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Takayama
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Saito
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Iwamoto
authors.forename: Jay Z
authors.initials: JZ
authors.lastname: Yeh
authors.forename: Toshio
authors.initials: T
authors.lastname: Narahashi
mesh_terms: 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
chemical_list: D002147:Calmodulin; D019209:Troponin C; D029867:Xenopus Proteins; D002118:Calcium