[Excitation of the hydrogen bond by the energy of hydrolysis of adenosine-5'-triphosphate]. / Vozbuzhdenie vodorodnoi sviazi za schet énergii gidroliza adenozin-5'-trifosfata.

The model of muscle contraction suggested in [1] is based on the hypothesis that the first step of the conversion of chemical energy delta E (which is stored in adenosine-5'-triphosphate) is the excitation of the hydrogen bond in the actin-myosin system with a simultaneous hydrolysis of the adenosine-5'-triphosphate molecule. As a consequence, the potential barrier is decreased, and the break of the macroergic bond adenosine-5'-triphosphate-phosphate is facilitated. With the delta E value exceeding the excitation energy of the H-bond, this process represents an exothermic reaction. A simple model of this process is constructed, and its probability depending on temperature and the mutual position of the H-bond and the adenosine-5'-triphosphate molecule is estimated.

[Statistics on actin globule chains, stretched by hydrogen bonds, and the Hill law in quantum mechanics theory of muscle contraction]. / Statistika tsepochek aktinovykh globul, rastianutykh vodorodnymi sviaziami, i zakon Khilla v kvantovo-mekhanicheskoi teorii myshechnogo sokrashcheniia.

The process of sarcomere membranes approaching under the action of actin and myosin filament stretching is studied theoretically. In elaboration of previous studies it is supposed that this stretching is due to the formation of hydrogen bonds excited by the energy of ATP splitting. A possibility for the hydrogen bond breakage at different stages of contraction is considered to be the greater the more are the polymers stretched, and the larger statistical scatter in the moments of H-bonds formation at different filaments if it is supposed that sarcomere contraction occurs much slower than stretching of each separate filament. As a result, one obtains a relationship between the rate of contraction and the external force which is close to the Hill's law, and the external force efficiency of a muscle contraction and heat extraction value are related to parameters of polymers and their properties.

[Cleavage time for a hydrogen bond under a load]. / Vremia razryva vodorodnoi sviazi, nakhodiashcheisia pod nagruzkoi.

Statistics of the hydrogen bond formation and break in a bundle of actin and myosin filaments realizing the attractive force in the sarcomere of a muscle is studied. Purely mechanical problem of the attractive-force formation and motion of myosin heads and action globules under their action is supplemented by accounting for the irreversible processes: 1. Thermal de-excitation of the latter in the chain of hydrogen bond during the elementary act of the ATP energy use resulting in fixing the extended actin filament. 2. Break of the hydrogen bonds, realizing this fixing, due to thermal fluctuations for the time tau. The average life-time turns out to be the order of time necessary for the movement of z-membrane sarcomere for the value of action filament extension delta 1, which is necessary for the process of muscle contraction to be continued.

Excited hydrogen bonds in the molecular mechanism of muscle contraction.

The mechanism of muscle contraction is considered. The hydrolysis of an ATP molecule is assumed to produce the excitation of hydrogen bonds A--H...B between electronegative atoms A and B, which are contained in the myosin head and actin filament. This excitation energy epsilon f depends on the interatomic distance AB = R and generates the tractive force f = -delta epsilon f/delta R, that makes atoms AB approach each other. The swing of the myosin head results in macroscopic mutual displacement of actin and myosin polymers. The motion of the actin filament under the action of this force is studied. The conditions under which a considerable portion of the excitation energy converts into the potential tension energy of the actin filament are analysed, and the probability of higher muscle efficiency existence is discussed.

[Heat transitions in DNA molecule. The life-time of excited h-b-1 hydrogen bond in paired guanine-cytosine bases]. / Teplovye perekhody v molekule DNK. Vremia zhizni vozbuzhdennoi vodorodnoi sviazi h-b-1 v sparennykh osnovaniiakh guanin-tsitozin.

A theory of radiationless transitions of protons of the hydrogen bonds between the paired DNA bases is constructed. The lifetime of excited h-b-1 bond in guanine-cytosine pair is found to be 4.6 x 10(-9) sec. The dependence of frequencies, amplitudes and normal coordinates of heavy atoms (N, O) on the state of H-bond (ground or excited) are taken into account.