Biomaterial Database

Induced potential model for muscular contraction mechanism, including two attached states of myosin head. 1998

T Mitsui, and S Kumagai, and H Chiba, and H Yoshimura, and H Ohshima

Department of Physics, School of Science and Technology, Meiji University, Kawasaki, Japan.

The model for myosin head motion along an actin filament as proposed by Mitsui & Chiba [(1996). J. theor. Biol. 182, 147-159] is here modified so that it can explain the isometric tension and isotonic velocity transients having the same parameter values as the stationary filament sliding. The modified model differs in that a myosin head forms a complex with two actin molecules in an actin filament and has two attached states in the complex instead of three. Thus an incremental step in the myosin head motion is equal to the F-actin monomer repeat (5.46 nm). Muscle properties concerning the stationary filament sliding are calculated with new parameters in a manner similar to that of Mitsui-Chiba, with the results being qualitatively similar to theirs. In studying the transient phenomena, a quantitative expression is given for the potential energy of the myosin head in the complex, and two rate constants are applied to the kinetics of the head. The time course of tension recovery after a quick length change is determined by calculating the statistical distribution of the head in the two attached states, which conforms to experimental observations by Ford et al. [(1977). J. Physiol. 269, 441-515]. The tension variations T1/T0 and T2/T0 calculated with parameters determined from the analysis of stationary filament slidings are in fairly good agreement with the experimental data by Ford et al. The model suggests that a large fluctuation exists in the relative position between the actin and myosin filaments even when the load on a muscle is kept constant. Taking this fluctuation into account explains the characteristics of the isotonic velocity transient observed by Civan & Podolsky.

UI	MeSH Term	Description	Entries
D007537	Isometric Contraction	Muscular contractions characterized by increase in tension without change in length.	Contraction, Isometric,Contractions, Isometric,Isometric Contractions
D007551	Isotonic Contraction	Muscle contraction with negligible change in the force of contraction but shortening of the distance between the origin and insertion.	Contraction, Isotonic,Contractions, Isotonic,Isotonic Contractions
D008954	Models, Biological	Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.	Biological Model,Biological Models,Model, Biological,Models, Biologic,Biologic Model,Biologic Models,Model, Biologic
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009218	Myosins	A diverse superfamily of proteins that function as translocating proteins. They share the common characteristics of being able to bind ACTINS and hydrolyze MgATP. Myosins generally consist of heavy chains which are involved in locomotion, and light chains which are involved in regulation. Within the structure of myosin heavy chain are three domains: the head, the neck and the tail. The head region of the heavy chain contains the actin binding domain and MgATPase domain which provides energy for locomotion. The neck region is involved in binding the light-chains. The tail region provides the anchoring point that maintains the position of the heavy chain. The superfamily of myosins is organized into structural classes based upon the type and arrangement of the subunits they contain.	Myosin ATPase,ATPase, Actin-Activated,ATPase, Actomyosin,ATPase, Myosin,Actin-Activated ATPase,Actomyosin ATPase,Actomyosin Adenosinetriphosphatase,Adenosine Triphosphatase, Myosin,Adenosinetriphosphatase, Actomyosin,Adenosinetriphosphatase, Myosin,Myosin,Myosin Adenosinetriphosphatase,ATPase, Actin Activated,Actin Activated ATPase,Myosin Adenosine Triphosphatase
D000199	Actins	Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.	F-Actin,G-Actin,Actin,Isoactin,N-Actin,alpha-Actin,alpha-Isoactin,beta-Actin,gamma-Actin,F Actin,G Actin,N Actin,alpha Actin,alpha Isoactin,beta Actin,gamma Actin
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia