The spontaneous oscillatory contraction（SPOC） of myofibrils is the essential property inherent to the contractile system of muscle. Muscle contraction results from cyclic interactions between actin filament and myos...The spontaneous oscillatory contraction（SPOC） of myofibrils is the essential property inherent to the contractile system of muscle. Muscle contraction results from cyclic interactions between actin filament and myosin II which is a dimeric motor protein with two heads. Taking the two heads of myosin II as an indivisible element and considering the effects of cooperative behavior between the two heads on rate constants in the mechanochemical cycle, the present work proposes the tenstate mechanochemical cycle model for myosin II dimer. The simulations of this model show that the proportion of myosin II in different states periodically changes with time, which results in the sustained oscillations of contractive tension, and serves as the primary factor for SPOC. The good fit of this model to experimental results suggests that the cooperative interaction between the two heads of myosin II dimer may be one of the underlying mechanisms for muscle contraction.展开更多
A dynalnic model of skeletal muscle is developed to describe its activation kinetics and contraction dynamics based on the collective working mechanism of myosin II motors with a statistical mechanics method. Accordin...A dynalnic model of skeletal muscle is developed to describe its activation kinetics and contraction dynamics based on the collective working mechanism of myosin II motors with a statistical mechanics method. According to the structure of sar- comeres arranged in series and in parallel, the mechanical properties of skeletal muscle are studied. This model reveals the re- lations between action potential and muscle characteristics. It is shown that calcium concentration in sarcoplasmic （SP） in- creases linearly with the increasing stimulation frequency and gradually reaches saturation. Active force and contraction veloc- ity follow the trend of calcium concentration and reach a peak value at the maximum stimulation frequency. Contraction ve- locity is inversely proportional to the load while the contraction power increases to maximum and then reduces to zero with the increasing load. These properties are consistent with published physiological experimental results of skeletal muscle.展开更多
基金Project supported by Research Program of Science and Technology at Universities of Inner Mongolia Autonomous Region,China(Grant Nos.NJZY16493and NJZC17458)
文摘The spontaneous oscillatory contraction（SPOC） of myofibrils is the essential property inherent to the contractile system of muscle. Muscle contraction results from cyclic interactions between actin filament and myosin II which is a dimeric motor protein with two heads. Taking the two heads of myosin II as an indivisible element and considering the effects of cooperative behavior between the two heads on rate constants in the mechanochemical cycle, the present work proposes the tenstate mechanochemical cycle model for myosin II dimer. The simulations of this model show that the proportion of myosin II in different states periodically changes with time, which results in the sustained oscillations of contractive tension, and serves as the primary factor for SPOC. The good fit of this model to experimental results suggests that the cooperative interaction between the two heads of myosin II dimer may be one of the underlying mechanisms for muscle contraction.
基金supported by the National Natural Science Foundation of China (Grant No. 61075101/60643002)the Research Fund of State Key Lab of MSV,China (Grant No. MSV-2010-1)+1 种基金the Science and Technology Intercrossingthe Medical and Technology Intercrossing Research Foundation of Shanghai Jiao Tong University (Grant No. YG2010ZD101)
文摘A dynalnic model of skeletal muscle is developed to describe its activation kinetics and contraction dynamics based on the collective working mechanism of myosin II motors with a statistical mechanics method. According to the structure of sar- comeres arranged in series and in parallel, the mechanical properties of skeletal muscle are studied. This model reveals the re- lations between action potential and muscle characteristics. It is shown that calcium concentration in sarcoplasmic （SP） in- creases linearly with the increasing stimulation frequency and gradually reaches saturation. Active force and contraction veloc- ity follow the trend of calcium concentration and reach a peak value at the maximum stimulation frequency. Contraction ve- locity is inversely proportional to the load while the contraction power increases to maximum and then reduces to zero with the increasing load. These properties are consistent with published physiological experimental results of skeletal muscle.
