title: [Effect of the C-terminal actin-binding sites of caldesmon on the interaction of actin with myosin].
abstract: TRITC-phalloidin or FITC-labeled F-actin of ghost muscle fibers was bound to tropomyosin and C-terminal recombinant fragments of caldesmon CaDH1 (residues 506-793) or CaDH2 (residues 683-767). After that the fibers were decorated with myosin subfragment 1. In the absence of caldesmon fragments, subfragment 1 interaction with F-actin caused changes in parameters of polarized fluorescence, that were typical of "strong" binding of myosin heads to F-actin and of the "switched on" conformational state of actin. CaDH1 inhibited, whereas CaDH2 activated the effect of subfragment 1. It is suggested that C-terminal part of caldesmon may modulate the transition of F-actin subunits from the "switched on" to the "switched off" state.
authors.affiliation: Institute of Cytology RAS, St. Petersburg.
authors.forename: P G
authors.initials: PG
authors.lastname: Vikhorev
authors.forename: S V
authors.initials: SV
authors.lastname: Avrova
authors.forename: V S
authors.initials: VS
authors.lastname: Ermakov
authors.forename: O
authors.initials: O
authors.lastname: Copeland
authors.forename: S B
authors.initials: SB
authors.lastname: Marston
authors.forename: Iu S
authors.initials: IuS
authors.lastname: Borovikov
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D002148:Calmodulin-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes; D009218:Myosins / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D011817:Rabbits
chemical_list: D000199:Actins; D002148:Calmodulin-Binding Proteins; D005456:Fluorescent Dyes; D009218:Myosins
vernacular_title: Vliianie C-kontsevykh aktinsviazyvaiushchikh saĭtov kal'desmona na vzaimodeĭstvie aktina s miozinom.