caa a22 4500 47574487X CHVBK 20180406123510.0 cr unu---uuuuu 170329e20001001xx s 000 0 eng 10.1023/A:1005661123914 doi (NATIONALLICENCE)springer-10.1023/A:1005661123914 A-band architecture in vertebrate skeletal muscle: polarity of the myosin head array [Elektronische Daten] [Marie Cantino, L. Brown, M. Chew, P. Luther, J. Squire] Despite extensive knowledge of many muscle A-band proteins (myosin molecules, titin, C-protein (MyBP-C)), details of the organization of these molecules to form myosin filaments remain unclear. Recently the myosin head (crossbridge) configuration in a relaxed vertebrate muscle was determined from low-angle X-ray diffraction (Hudson et al. (1997), J Mol Biol 273: 440-455). This showed that, even without C-protein, the myosin head array displays a characteristic polar pattern with every third 143 Å-spaced crossbridge level particularly prominent. However, X-ray diffraction cannot determine the polarity of the crossbridge array relative to the neighbouring actin filaments; information crucial to a proper understanding of the contractile event. Here, electron micrographs of negatively-stained goldfish A-segments and of fast-frozen, freeze-fractured plaice A-bands have been used to determine the resting myosin head polarity relative to the M-band. In agreement with the X-ray data, the prominent 429 Å-spaced striations are seen outside the C-zone, where no non-myosin proteins apart from titin are thought to be located. The head orientation is with the concave side of the curved myosin heads (containing the entrance to the ATP-binding site) facing towards the M-band and the convex surface (containing the actin-binding region at one end) facing away from the M-band. Kluwer Academic Publishers, 2000 Cantino Marie Department of Physiology and Neurobiology, University of Connecticut, 06269-2131, Storrs, CT, USA aut Brown L. Department of Physiology and Neurobiology, University of Connecticut, 06269-2131, Storrs, CT, USA aut Chew M. Biological Structure and Function Section, Biomedical Sciences Division, Imperial College of Science, Technology and Medicine, SW7 2AZ, London, UK aut Luther P. Biological Structure and Function Section, Biomedical Sciences Division, Imperial College of Science, Technology and Medicine, SW7 2AZ, London, UK aut Squire J. Biological Structure and Function Section, Biomedical Sciences Division, Imperial College of Science, Technology and Medicine, SW7 2AZ, London, UK aut Journal of Muscle Research & Cell Motility Kluwer Academic Publishers 21/7(2000-10-01), 681-690 0142-4319 21:7<681 2000 21 10974 https://doi.org/10.1023/A:1005661123914 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1005661123914 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Cantino Marie Department of Physiology and Neurobiology, University of Connecticut, 06269-2131, Storrs, CT, USA aut NATIONALLICENCE 700 1- Brown L. Department of Physiology and Neurobiology, University of Connecticut, 06269-2131, Storrs, CT, USA aut NATIONALLICENCE 700 1- Chew M. Biological Structure and Function Section, Biomedical Sciences Division, Imperial College of Science, Technology and Medicine, SW7 2AZ, London, UK aut NATIONALLICENCE 700 1- Luther P. Biological Structure and Function Section, Biomedical Sciences Division, Imperial College of Science, Technology and Medicine, SW7 2AZ, London, UK aut NATIONALLICENCE 700 1- Squire J. Biological Structure and Function Section, Biomedical Sciences Division, Imperial College of Science, Technology and Medicine, SW7 2AZ, London, UK aut NATIONALLICENCE 773 0- Journal of Muscle Research & Cell Motility Kluwer Academic Publishers 21/7(2000-10-01), 681-690 0142-4319 21:7<681 2000 21 10974 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer