[Explanation of a nonlinear course of tension changes after rapid stepwise shortening of muscles using a new model of the actomyosin bridge].
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Actomyosin↗
Biomedical subjects
N P Sidorenko
Publications and source records attributed to N P Sidorenko.
[Relation between the number of closed cross-bridges and the load during muscle contraction].
Analytic expressions for the relationships between the number of attached cross-bridges and the load and velocity of muscle contraction are obtained from Deshcherevsky's kinetic theory of muscle contractions. The comparison of these expressions with the experimental relationships known from literature is carried out their good agreement is shown.
Animals↗
[Estimating the length of actomyosin cross-bridge contraction].
In the work by Yanagida et al. (1985) the distance was measured by which the myosin cross-bridge moved along the actin filament during one cycle of ATP hydrolysis. This distance, in the opinion of the authors, must be equal to the length of the cross-bridge power stroke. However the measured distance (60 divided by 68 nm) was considerably greater than the cross-bridge power stroke measured earlier by other methods. In the present paper it is shown on the basis of the kinetic theory of muscle contraction of V. I. Deshcherevsky that the distance, the cross-bridge passed during one cycle of ATP hydrolysis must be nearly 5 times greater than the cross-bridge power stroke. The estimation of the length of the cross-bridge power stroke from the Yanagida's et al. data on the basis of the kinetic model gives 12 divided by 14 nm which is in a good accordance with the results obtained earlier.
Actomyosin↗
[Oscillating biological processes at the molecular level].
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Catalysis↗
[Do enzymes decrease the activation energy?].
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Catalase↗
[Generalized form of kinetic equations of enzymatic catalysis from the calculation of protein macromolecular relaxation].
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Catalysis↗
[Model of two-headed myosin cross-bridge and possibility of its motion in skeletal muscles].
The model of "two-headed" myosin cross-bridge is proposed whose motion is realized by stepping of its two heads on two actin filaments. By Offer and Elliott graphical method possible attachment sites on the actin filaments are determined for skeletal muscles and the geometrical possibility of "two-headed" cross-bridge stepping during muscle contraction is shown. It can be assumed that the recently discovered in Characean cells motion of oligomeric myosin along actin filaments can proceed by a similar mechanism.
Actins↗
[The possible restructuring of myosin bridges on the thick filament surface, caused by muscle activation].
In one of author's previous work the stepping cross-bridge model has been proposed. It was shown that the structure of actin filaments and their arrangement in muscle sarcomere ensure the whole necessary condition for the stepping cross-bridges movement in contracting muscle. In this work the requirements put on the thick filament structure by the stepping cross-bridge model are determined. The consideration leads to the conclusion on the rearrangement of myosin cross-bridges on the thick filament surface caused by the activation of the muscle.
Muscle Contraction↗
[The possible functional role of the "spiral-helix" transition in the myosin rod in muscle contraction].
In Harrington's model, local helix-coil transition in coiled-coil portion of myosin is considered to be an origin of force generation in muscle. However, the detailed analysis of this model leads to the conclusion about the different functional role of the helix-coil transition in contracting muscle.
Animals↗
[Anomalous changes in the rheological properties of muscle protein solutions in the final stages of ATP hydrolysis].
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Actins↗
[Thick filament shortening as a result of filament sliding].
It is usually accepted that the phenomenon of thick filament shortening contradicts the sliding filament theory and cross-bridge mechanism of force generation. However, some peculiarity of experimental data indicate the thick filament shortening can be a corollary of the interaction of myosin cross-bridges with the actin filaments "wrong" polarities in sarcomeres with the actin filaments double overlap formed in the results of the filament sliding.
Actins↗
[Some new perspectives on V. I. Deshcherevskiy's kinetic theory of muscle contraction].
Deshcherevsky's kinetic theory of muscle contraction (Deshcherevsky, 1968, 1971) is considered in the light of the modern experimental data. The data are discussed, which support the validity of some propositions and conclusions of the theory, including the postulate on the negligibly small probability of pulling cross-bridge detachment. It is shown that if this postulate is accepted and the distance between the neighbouring actin sites for the given myosin cross-bridge attachment on the actin filament is taken as an actin filament half-turn (Sydorenko, 1982, 1984), then simple explanations, which don't contradict the cross-bridge hypothesis of force generation, could be given to a number of muscle behaviour features such as the high efficiency, stepwise shortening, repeated tension recovery after repeated forced step-wise shortening of activated muscle with the time-interval less than 10 ms, step-size up to 90nm powered by a single ATP molecule and so on.
Adenosine Triphosphate↗