title: Increase in the molecular weight and radius of gyration of apocalmodulin induced by binding of target peptide: evidence for complex formation.
abstract: Small-angle X-ray scattering was used to investigate a complex state of apocalmodulin induced by the binding of a Ca(2+)/calmodulin-dependent protein kinase IV calmodulin target site. Upon binding of the peptide, the molecular weight for apocalmodulin increased by 8.4%, which provides direct evidence for the formation of a calmodulin/target peptide complex. Comparison of the radius of gyration and Kratky plots of the apocalmodulin/peptide complex with those of apocalmodulin indicates that the overall conformation remains unchanged but the flexibility of the central linker decreases. An analysis of residue pairs between calmodulin and the target peptides suggests that the complex formation is induced by electrostatic interactions and subsequent van der Waals interactions.
authors.affiliation: Graduate Program of Human Sensing and functional Sensor Enigineering, Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jo-nan, Yonezawa 992-8510, Japan. yizumi@dip.yz.yamagata-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Izumi
authors.forename: S
authors.initials: S
authors.lastname: Kuwamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Jinbo
authors.forename: H
authors.initials: H
authors.lastname: Yoshino
mesh_terms: D001059:Apoproteins / Q000737:chemistry*; D054734:Calcium-Calmodulin-Dependent Protein Kinase Type 4; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics; D002147:Calmodulin / Q000737:chemistry*; D006801:Humans; D046911:Macromolecular Substances; D008970:Molecular Weight; D010455:Peptides / Q000737:chemistry* / Q000235:genetics; D011485:Protein Binding / Q000502:physiology; D011487:Protein Conformation; D012542:Scattering, Radiation; D014965:X-Rays
chemical_list: D001059:Apoproteins; D002147:Calmodulin; D046911:Macromolecular Substances; D010455:Peptides; C517683:CAMK4 protein, human; D054734:Calcium-Calmodulin-Dependent Protein Kinase Type 4; D017871:Calcium-Calmodulin-Dependent Protein Kinases