title: Activation of myosin light chain kinase requires translocation of bound calmodulin.
abstract: A novel translocation step is inferred from structural studies of the interactions between the intracellular calcium receptor protein calmodulin (CaM) and one of its regulatory targets. A mutant of CaM missing residues 2-8 (DeltaNCaM) binds skeletal muscle myosin light chain kinase with high affinity but fails to activate catalysis. Small angle x-ray scattering data reveal that DeltaNCaM occupies a position near the catalytic cleft in its complex with the kinase, whereas the native protein translocates to a position near the C-terminal end of the catalytic core. Thus, CaM residues 2-8 appear to facilitate movement of bound CaM away from the vicinity of the catalytic cleft.
authors: Bioscience Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors: J K
authors: JK
authors: Krueger
authors: S C
authors: SC
authors: Gallagher
authors: G
authors: G
authors: Zhi
authors: R
authors: R
authors: Geguchadze
authors: A
authors: A
authors: Persechini
authors: J T
authors: JT
authors: Stull
authors: J
authors: J
authors: Trewhella
mesh_terms: D000818:Animals; D002147:Calmodulin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D008958:Models, Molecular; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism*; D021381:Protein Transport; D017384:Sequence Deletion; D014961:X-Ray Diffraction
chemical_list: D002147:Calmodulin; D009219:Myosin-Light-Chain Kinase