Summary
Structural changes of crossbridges during isometric contraction have been studied by electron microscopy. Chemically skinned rabbit fibres were rapidly frozen either in activating solution or in ATP-free (rigor) solution, freeze-substituted and embedded. Longitudinal sections of muscle fibres show that the number of crossbridges in active fibres (isometric contraction) is approximately the same as in rigor fibres. Crossbridges of the active and rigor states differ in their shapes, angles and manner of arrangement on the thin filaments. In rigor many crossbridges are wide near the thin filaments and narrow near the thick filament shafts; in active fibres they have more uniform width along their length. The angle of the crossbridges in active fibres is somewhat variable. The average angle is ∼90° to the filament axis. The crossbridges are arranged on the thin filament retaining the 14.3 nm thick filament periodicity. The crossbridges in rigor are tilted and their arrangement near the thin filament reveals the 36 nm actin periodicity. The variability in the shapes of the crossbridges in active fibres is still higher when we look at them in cross-sections of muscle fibres. The crossbridge shapes in the cross-sections were classified and the relative frequency of different shapes was determined. The shapes that are commonly observed in active fibres are similar in that the majority of the mass of the crossbridges is farther away from the thin filament than the crossbridges in rigor fibres.
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References
Amemiya, Y., Wakabayashi, K., Tanaka, H., Ueno, Y. & Miyahara, J. (1987) Laser-stimulated luminescence used to measure X-ray diffraction of a contracting striated muscle. Science 237, 164–8.
Applegate, D. & Flicker, P. (1987) New states of actomyosin. J. Biol. Chem. 262, 6856–63.
Barnett, V. A. & Thomas, D. D. (1989) Microsecond rotational motion of spin-labelled myosin heads during isometric muscle contraction. Biophys. J. 56, 517–23.
Bridgman, P. C. & Reese, T. S. (1984) The structure of cytoplasm in directly frozen cultured cells. I. Filamentous meshworks and the cytoplasmic ground substance. J. Cell Biol. 99, 1655–68.
Cooke, R., Crowder, M. S. & Thomas, D. D. (1982) Orientation of spin labels attached to cross-bridges in contracting muscle fibres. Nature (Lond.) 300, 776–8.
Craig, R., Greene, L. E. & Eisenberg, E. (1985) Structure of the actin-myosin complex in the presence of ATP. Proc. Natl. Acad. Sci. USA 82, 3247–51.
Edelmann, L. (1989) The contracting muscle: a challenge for freeze-substitution and low temperature embedding. Scanning Microsc. Suppl. 3, 41–252.
Endo, M. & Iino, M (1980) Specific perforation of muscle cell membranes with preserved SR functions by saponin treatment. J. Muscle Res. Cell Motil. 1, 89–100.
Fajer, P. G., Fajer, E. A. & Thomas, D. D. (1990) Myosin heads have a broad orientational distribution during isometric muscle contraction: time-resolved EPR studies using caged ATP. Proc. Natl. Acad. Sci. USA 87, 5538–42.
Frado, L.-L. & Craig, R. (1992) Electron microscopy of the actin-myosin head complex in the presence of ATP. J. Mol. Biol. 223, 391–7.
Freundlich, A., Luther, P. K. & Squire, J. M. (1980) High-voltage electron microscopy of crossbridge interactions in striated muscle. J. Muscle Res. Cell Motil. 1, 321–43.
Goldman, Y. E. (1987) Kinetics of the actomysin ATPase in muscle fibres. Ann. Rev. Physiol. 49, 637–54.
Goldman, Y. E. & Simmons, R. M. (1977) Active and rigor muscle stiffness. J. Physiol. 269, 55–7.
Haselgrove, J. C. & Huxley, H. E. (1973) X-ray evidence for radial cross-bridge movement and for the sliding filament model in actively contracting skeletal muscle. J. Mol. Biol. 77, 549–68.
Haselgrove, J. C. (1975) X-ray evidence for conformational changes in the myosin filaments of vertebrate striated muscle. J. Mol. Biol. 92, 113–43.
Haselgrove, J. C. & Reedy, M. K. (1978) Modeling rigor crossbridge patterns in muscle. Initial studies of the rigor lattice of insect flight muscle. Biophys. J. 24, 713–28.
Heuser, J. E. (1987) Crossbridges in insect flight muscles of the blowfly (Sarcophaga bullata). J. Muscle Res. Cell Motil. 8, 303–21.
Heuser, J. E., Reese, T. S., Dennis, M. J., Jan, Y., Jan, L. & Evans, L. (1979) Synaptic vesicle exocytosis captured by quick freezing and correlated with quantal transmitter release. J. Cell Biol. 81, 275–300.
Hirose, K. & Wakabayashi, T. (1988) Thin filaments of rabbit skeletal muscle are in helical register. J. Mol. Biol. 204, 797–801.
HIROSE, K., LENART, T. D., MURRAY, J. M., FRANZINI-ARMSTRONG, C. & GOLDMAN, Y. E. (1993) Flash and smash: rapid freezing of muscle fibers activated by photolysis of caged ATP. Biophys. J. (in press).
Huxley, H. E. (1963) Electron microscope studies on the structure of natural and synthetic protein filaments from striated muscle. J. Mol. Biol. 7, 281–308.
Huxley, H. E. (1969) The mechanism of muscular contraction. Science 164, 1356–66.
Huxley, H. E. & Brown, W. (1967) The low-angle X-ray diagram of vertebrate striated muscle and its behaviour during contraction and rigor. J. Mol. Biol. 30, 383–434.
Huxley, H. E., Faruqi, A. R. & Kress, M. (1982) Time-resolved X-ray diffraction studies of the myosin layer-line reflections during muscle contraction. J. Mol. Biol. 158, 637–84.
Katayama, E. (1989) The effects of various nucleotides on the structure of actin-attached myosin subfragment-1 studied by quick-freeze deep-etch electron microscopy. J. Biochem. 106, 751–70.
LENART, T. D., FRANZINI-ARMSTRONG, C. & GOLDMAN, Y. E. (1992) Ultrastructure of frog sartorius muscle fibers quickly frozen following activation by caged Ca2+ photolysis. Biophys. J. 61, A286.
Lepault, J., Erk, I., Nicolas, G. & Ranck, J.-L. (1991) Timeresolved cryo-electron microscopy of vitrified muscular components. J. Microscopy 161, 47–57.
Lowy, J. & Poulsen, F. R. (1987) X-ray study of myosin heads in contracting frog skeletal muscle. J. Mol. Biol. 194, 595–600.
Matsubara, I., Yagi, N. & Hashizume, H. (1975) Use of an X-ray television for diffraction of the frog striated muscle. Nature (Lond.) 255, 728–9.
Milligan, R. A. & Flicker, P. F. (1987) Structural relationships of actin, myosin and tropomyosin revealed by cryo-electron microscopy. J. Cell Biol. 105, 29–39.
Moore, P. B., Huxley, H. E. & Derosier, D. J. (1970) Three-dimensional reconstruction of F-actin, thin filaments and decorated thin filaments. J. Mol. Biol. 50, 279–95.
Nassar, R., Wallace, N. R., Taylor, I. & Sommer, J. R. (1986) The quick-freezing of single intact skeletal muscle fibers at known time intervals following electrical stimulation. Scanning Electron Microsc. I, 309–28.
Poole, K. J. V., Maeda, Y., Rapp, G. & Goody, R. S. (1991) Dynamic X-ray diffraction measurements following photolytic relaxation and activation of skinned rabbit psoas fibres. Adv. Biophys. 27, 63–75.
Reedy, M. K., (1968) Ultrastructure of insect flight muscle. I. Screw sense and structural grouping in the rigor crossbridge lattice. J. Mol. Biol. 31, 155–76.
Reedy, M. K. & Reedy, M. C. (1985) Rigor crossbridge structure in tilted single filament layers and flared-X formations from insect flight muscle. J. Mol. Biol. 185, 145–76.
Reedy, M. K., Holmes, K. C. & Tregear, R. T. (1965) Induced changes in orientation of the cross-bridges of glycerinated insect flight muscle. Nature (Lond.) 207, 1276–80.
Squire, J. M. (1972) General model of myosin filament structure. II. Myosin filaments and crossbridge interactions in vertebrate striated and insect flight muscle. J. Mol. Biol. 72, 125–38.
Squire, J. M. & Harford, J. J. (1988) Actin filament organization and myosin head labeling patterns in vertebrate skeletal muscles in the rigor and weak binding states. J. Muscle Res. Cell Motil. 9, 344–58.
Taylor, K. A. & Amos, L. A. (1981) A new model for the geometry of the binding of myosin crossbridges to muscle thin filaments. J. Mol. Biol. 147, 297–324.
Taylor, K. A., Reedy, M. C., Cordova, L. & Reedy, M. K. (1989) Three-dimensional image reconstruction of insect flight muscle. I. The rigor myac layer. J. Cell Biol. 109, 1085–102.
Toyoshima, T. & Wakabayshi, T. (1985) Three-dimensional image analysis of the complex of thin filaments and myosin molecules from skeletal muscle. IV. Reconstitution from minimal- and high-dose images of the actintropomyosin-myosin subfragment-1 complex. J. Biochem. 97, 219–43.
Trombitás, K., Baatsen, P. H. W. W. & Pollack, G. H. (1986) Rigor bridge angle: effects of applied stress and preparative procedure. J. Ultrastruct. Mol. Struct. Res. 97,39–49.
Tsukita, S. & Yano, M. (1985) Actomyosin structure in contracting muscle detected by rapid freezing. Nature (Lond.) 317, 182–4.
Tsukita, S. & Yano, M. (1988) Instantaneous view of actomyosin structure in shortening muscle. In Molecular Mechanism of Muscle Contraction (edited by Sugi, H. and Pollack, G. H.) pp. 49–61. New York: Plenum Publishing Corp.
Usukura, J., Yorifuji, H. & Yamada, E. (1982) Freeze-substitution using various kinds of fixative. J. Electron Microsc. 31 301.
Usukura, J., Akahori, H., Takahashi, H. & Yamada, E. (1983) An improved device for rapid freezing using liquid helium. J. Electron Microsc. 32, 180–5.
Varriano-Marston, E., Franzini-Armstrong, C. & Hasel-Grove, J. C. (1984) The structure and disposition of crossbridges in deep etched fish muscle. J. Muscle Res. Cell Motil. 5, 363–86.
Veilleman, P. F. (1977) Robust nonlinear data smoothers: definitions and recommendations. Proc. Natl. Acad. Sci. USA 74, 434–6.
Yagi, N., O'Brien, E. J. & Matsubara, I. (1981) Changes of thick filament structure during contraction of frog striated muscle. Biophys. J. 33, 121–38.
ZOT, H. G., MAUPIN, P. & POLLARD, T. D. (1990) Evidence that crosslinked acto-subfragment-1 is dissociated but tethered in the presence of ATP. Biophys. J. 57, 410a.
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Hirose, K., Wakabayashi, T. Structural change of crossbridges of rabbit skeletal muscle during isometric contraction. J Muscle Res Cell Motil 14, 432–445 (1993). https://doi.org/10.1007/BF00121295
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DOI: https://doi.org/10.1007/BF00121295