WordNet

the commonest protein in muscle; a globulin that combines with actin to form actomyosin

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1. 肥大型心筋症：遺伝子変異および臨床遺伝子検査 hypertrophic cardiomyopathy gene mutations and clinical genetic testing
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3. 肥大型心筋症：自然経過および予後 hypertrophic cardiomyopathy natural history and prognosis
4. 急性大動脈解離の臨床的特徴および診断 clinical features and diagnosis of acute aortic dissection
5. 心筋における興奮収縮連関 excitation contraction coupling in myocardium

English Journal

Flexibility within the heads of muscle myosin-2 molecules.

Billington N1, Revill DJ1, Burgess SA1, Chantler PD2, Knight PJ3.Author information 1School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.2Unit of Molecular and Cellular Biology, Royal Veterinary College, University of London, Royal College Street, London NW1 0TU, UK.3School of Molecular and Cellular Biology and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK. Electronic address: p.j.knight@leeds.ac.uk.AbstractWe show that negative-stain electron microscopy and image processing of nucleotide-free (apo) striated muscle myosin-2 subfragment-1 (S1), possessing one light chain or both light chains, is capable of resolving significant amounts of structural detail. The overall appearance of the motor and the lever is similar in rabbit, scallop and chicken S1. Projection matching of class averages of the different S1 types to projection views of two different crystal structures of apo S1 shows that all types most commonly closely resemble the appearance of the scallop S1 structure rather than the methylated chicken S1 structure. Methylation of chicken S1 has no effect on the structure of the molecule at this resolution: it too resembles the scallop S1 crystal structure. The lever is found to vary in its angle of attachment to the motor domain, with a hinge point located in the so-called pliant region between the converter and the essential light chain. The chicken S1 crystal structure lies near one end of the range of flexion observed. The Gaussian spread of angles of flexion suggests that flexibility is driven thermally, from which a torsional spring constant of ~23 pN·nm/rad² is estimated on average for all S1 types, similar to myosin-5. This translates to apparent cantilever-type stiffness at the tip of the lever of 0.37 pN/nm. Because this stiffness is lower than recent estimates from myosin-2 heads attached to actin, we suggest that binding to actin leads to an allosteric stiffening of the motor-lever junction.
Journal of molecular biology.J Mol Biol.2014 Feb 20;426(4):894-907. doi: 10.1016/j.jmb.2013.11.028. Epub 2013 Dec 9.
We show that negative-stain electron microscopy and image processing of nucleotide-free (apo) striated muscle myosin-2 subfragment-1 (S1), possessing one light chain or both light chains, is capable of resolving significant amounts of structural detail. The overall appearance of the motor and the le
PMID 24333017

Gly126Arg substitution causes anomalous behaviour of α-skeletal and β-smooth tropomyosins during the ATPase cycle.

Rysev NA1, Nevzorov IA2, Avrova SV1, Karpicheva OE1, Redwood CS3, Levitsky DI4, Borovikov YS5.Author information 1Laboratory of Mechanisms of Cell Motility, Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Avenue, St. Petersburg 194064, Russia.2Institute of Biotechnology, University of Helsinki, Viikinkaari 9, 00014 Helsinki, Finland.3Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK.4A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow 119071, Russia.5Laboratory of Mechanisms of Cell Motility, Institute of Cytology, Russian Academy of Sciences, 4 Tikhoretsky Avenue, St. Petersburg 194064, Russia. Electronic address: borovikov@incras.ru.AbstractTo investigate how TM stabilization induced by the Gly126Arg mutation in skeletal α-TM or in smooth muscle β-TM affects the flexibility of TMs and their position on troponin-free thin filaments, we labelled the recombinant wild type and mutant TMs with 5-IAF and F-actin with FITC-phalloidin, incorporated them into ghost muscle fibres and studied polarized fluorescence at different stages of the ATPase cycle. It has been shown that in the myosin- and troponin-free filaments the Gly126Arg mutation causes a shift of TM strands towards the outer domain of actin, reduces the number of switched on actin monomers and decreases the rigidity of the C-terminus of α-TM and increases the rigidity of the N-terminus of β-TMs. The binding of myosin subfragment-1 to the filaments shifted the wild type TMs towards the inner domain of actin, decreased the flexibility of both terminal parts of TMs, and increased the number of switched on actin monomers. Multistep alterations in the position of α- and β-TMs and actin monomers in the filaments and in the flexibility of TMs and F-actin during the ATPase cycle were observed. The Gly126Arg mutation uncouples a correlation between the position of TM and the number of the switched on actin monomers in the filaments.
Archives of biochemistry and biophysics.Arch Biochem Biophys.2014 Feb 1;543:57-66. doi: 10.1016/j.abb.2013.12.016. Epub 2013 Dec 25.
To investigate how TM stabilization induced by the Gly126Arg mutation in skeletal α-TM or in smooth muscle β-TM affects the flexibility of TMs and their position on troponin-free thin filaments, we labelled the recombinant wild type and mutant TMs with 5-IAF and F-actin with FITC-phalloidin, incor
PMID 24374033

1,3-Diethylurea-enhanced Mg-ATPase activity of skeletal muscle myosin with a converse effect on the sliding motility.

Wazawa T1, Yasui S, Morimoto N, Suzuki M.Author information 1Department of Materials Processing, Graduate School of Engineering, Tohoku University, Aoba-yama 02, Aoba-ku, Sendai 980-8579, Japan.AbstractWe investigate the effects of urea and its derivatives on the ATPase activity and on the in vitro motility of chicken skeletal muscle actomyosin. Mg-ATPase rate of myosin subfragment-1 (S1) is increased by 4-fold by 0.3M 1,3-diethylurea (DEU), but it is unaffected by urea, thiourea, and 1,3-dimethylurea at ≤1M concentration. Thus, we further examine the effects of DEU in comparison to those of urea as reference. In in vitro motility assay, we find that in the presence of 0.3M DEU, the sliding speeds of actin filaments driven by myosin and heavy meromyosin (HMM) are significantly decreased to 1/16 and 1/6.6, respectively, compared with the controls. However, the measurement of the actin-activated ATPase activity of HMM shows that the maximal rate, Vmax, is almost unchanged with DEU. Thus, the myosin-driven sliding motility of actin filaments is significantly impeded in the presence of 0.3M DEU, whereas the cyclic interaction of myosin with F-actin occurs during the ATP turnover, the rate of which is close to that without DEU. In contrast to DEU, 0.3M urea exhibits only modest effects on both actin-activated ATPase and sliding motility of actomyosin. Thus, DEU has the effect of uncoupling the sliding motility of actomyosin from its ATP turnover.
Biochimica et biophysica acta.Biochim Biophys Acta.2013 Dec;1834(12):2620-9. doi: 10.1016/j.bbapap.2013.08.003. Epub 2013 Aug 14.
We investigate the effects of urea and its derivatives on the ATPase activity and on the in vitro motility of chicken skeletal muscle actomyosin. Mg-ATPase rate of myosin subfragment-1 (S1) is increased by 4-fold by 0.3M 1,3-diethylurea (DEU), but it is unaffected by urea, thiourea, and 1,3-dimethyl
PMID 23954499