title: Parking problem and negative cooperativity of binding of myosin subfragment 1 to F-actin.
abstract: Previously we provided evidence that myosin subfragment 1 (S1) can bind either one (state 1) or two actin monomers (state 2) in solution and in muscle fiber. Here we present results of the kinetics study of binding of S1 to F-actin labeled with fluorescent dye pyrene. A transition from state 1 to state 2 depends on probability that the second actin is free, which is high when molar ratio of S1/actin (R) is less than 0.5, and it decreases dramatically when R>2.0 due to the parking problem. The kinetics data obtained at different molar ratios were well fitted by two binding states model. The sequential binding of myosin head initially with one actin monomer and then with the second actin monomer in F-actin can play a key role in force generation by actin-myosin and their directed movement.
authors.affiliation: Physics Department, University of Rhode Island, 2 Lippitt Rd., Kingston, RI 02881, USA.
authors.forename: Yana K
authors.initials: YK
authors.lastname: Reshetnyak
authors.forename: Cynthia N
authors.initials: CN
authors.lastname: Prudence
authors.forename: James
authors.initials: J
authors.lastname: Segala
authors.forename: Vladislav S
authors.initials: VS
authors.lastname: Markin
authors.forename: Oleg A
authors.initials: OA
authors.lastname: Andreev
mesh_terms: D000199:Actins / Q000737:chemistry*; D000818:Animals; D005456:Fluorescent Dyes / Q000737:chemistry; D007700:Kinetics; D008956:Models, Chemical; D015879:Myosin Subfragments / Q000737:chemistry*; D011485:Protein Binding; D011721:Pyrenes / Q000737:chemistry; D011817:Rabbits
chemical_list: D000199:Actins; D005456:Fluorescent Dyes; D015879:Myosin Subfragments; D011721:Pyrenes; C030984:pyrene