Summary
C-protein from chicken pectoralis muscle has been purified by sequential DEAE-Sephadex and hydroxyapatite chromatography and examined by transmission electron microscopy after spraying in glycerol onto mica and replicating by rotary shadowing with platinum. The most frequently observed particles were of three forms: rod-shaped, U-shaped and V-shaped. Within a size range of 15–40 nm these three groups accounted for 70% of over 800 particles categorized and measured. The remaining particles could not be classified. Since the relative abundance of each of these three forms was well in excess of any of the contaminating proteins detectable by SDS-polyacrylamide gel electrophoresis, we conclude that these variant forms represent C-protein molecules in differing conformations and/or deformations. Particles were observed which were intermediate between rod-shaped and tightly curved U-shaped forms, and between rod and acutely angled V-shaped forms. These results are compatible with a molecular model of a 32 nm × 3 nm flexible, rod-shaped C-protein monomer similar to one previously proposed from hydrodynamic studies and extend recent observations on the ultrastructure of cardiac C-protein.
Infrequently, a discontinuously larger V-shaped form was seen, possibly representing a C-protein dimer.
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References
Callaway, J. &Bechtel, P. J. (1981) C-protein from rabbit soleus (red) muscle.Biochem. J. 195, 463–9.
Craig, R. &Offer, G. (1976) The location of C-protein in rabbit skeletal muscle.Proc. R. Soc. Ser. B 192, 451–61.
Dennis, J. E., Shimizu, T., Reinach, F. C. &Fischman, D. A. (1984) Localization of C-protein isoforms in chicken skeletal muscle: ultrastructural detection using monoclonal antibodies.J. Cell Biol. 98, 1514–22.
Elliott, A. &Offer, G. (1978) Shape and flexibility of the myosin molecule.J. molec. Biol. 123, 505–19.
Godfrey, J. E. &Harrington, W. F. (1970) Self-association in the myosin system at high ionic strength. I. Sensitivity of the interaction to pH and ionic environment.Biochemistry 9, 886–93.
Hartzell, H. C. (1984) Phosphorylation of C-protein in intact amphibian cardiac muscle: correlation between32P incorporation and twitch relaxation.J. gen. Physiol. 83, 563–88.
Hartzell, H. C. &Sale, W. S. (1985) Structure of C-protein purified from cardiac muscle.J. Cell Biol. 100, 208–15.
Jeacocke, S. A. &England, P. J. (1980) Phosphorylation of a myofibrillar protein of Mr 150,000 in perfused rat heart, and the tentative identification of this as C-protein.FEBS Letts 122, 129–32.
Kawashima, M., Kitani S., Tanaka, T. &Obinata, T. (1984) Expression of C-protein isoforms during skeletal muscle development.Third International Congress on Cell Biology, P. 511. Tokyo: Japanese Society for Cell Biology.
Koretz, J. F. (1979) Effects of C-protein on synthetic myosin filament structure.Biophys. J. 27, 433–46.
Magid, A., Kontis, T., Ting-Beall, H. P. &Lucaveche, C. (1984) Elastic side-forces between thick filaments in vertebrate striated muscle and the possible role of C-protein.Biophys. J. 45, 155a.
Marshall, A. G. (1978) Forced march. InBiophysical Chemistry, p. 201. New York: John Wiley.
Moos, C., Offer, G., Starr, R. &Bennett, P. (1975) Interaction of C-protein with myosin, myosin rod and light meromyosin.J. molec. Biol. 97, 1–9.
Moos, C., Mason, C. M., Besterman, J. M., Feng, I. M. &Dubin, J. H. (1978) The binding of skeletal muscle C-protein to F-actin and its relation to the interaction of actin with myosin subfragment-1.J. molec. Biol. 124, 571–86.
Moos, C. (1981) Fluorescence microscope study of the binding of added C-protein to skeletal muscle myofibrils.J. Cell Biol. 90, 25–31.
Obinata, T., Kitani, S., Masaki, T. &Fischman, D. A. (1984) Coexistence of fast-type and slow type C-proteins in neonatal chicken breast muscle.Devl Biol. 105, 253–6.
Offer, G., Moos, C. &Starr, R. (1973) A new protein of the thick filaments of vertebrate skeletal myofibrils. Extraction, purification and characterization.J. molec. Biol. 74, 653–76.
Pepe, F. A. &Drucker, B. (1975) The myosin filament. III. C-protein.J. molec. Biol. 99, 609–17.
Reinach, F. C., Masaki, T., Shafiq, S., Obinata, T. &Fischman, D. A. (1982) Isoforms of C-protein in adult chicken skeletal muscle: detection with monoclonal antibodies.J. Cell Biol. 95, 78–84.
Reinach, F. C., Masaki, T. &Fischman, D. A. (1983) Characterization of the C-protein from posterior latissimus dorsi muscle of the adult chicken: heterogeneity within a single sarcomere.J. Cell Biol. 96, 297–300.
Squire, J. M., Harford, J. G., Edman, A. C. &Sjostrom, M. (1982) Fine structure of the A-band in cryosections. III. Crossbridge distribution and the axial structure of the human C-zone.J. molec. Biol. 155, 467–494.
Starr, R. &Offer, G. (1971) Polypeptide chain of intermediate molecular weight in myosin preparations.FEBS Letts 15, 40–4.
Starr, R. &Offer, G. (1978) The interaction of C-protein with heavy meromyosin and subfragment-2.Biochem. J. 171, 813–6.
Starr, R. &Offer, G. (1982) Preparation of C-protein, H-protein, X-protein and phosphofructokinase.Meth. Enzym. 85, 130–8.
Starr, R. &Offer, G. (1983) H-protein and X-protein. Two new components of the thick filaments of vertebrate skeletal muscle.J. molec. Biol. 170, 675–98.
Tyler, J. &Branton, D. (1980) Rotary shadowing of extended molecules dried from glycerol.J. Ultrastruct. Res. 71, 95–102.
Yamamoto, K. &Moos, C. (1983) The C-proteins of rabbit red, white and cardiac muscles.J. biol. Chem. 258, 8395–401.
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Swan, R.C., Fischman, D.A. Electron microscopy of C-protein molecules from chicken skeletal muscle. J Muscle Res Cell Motil 7, 160–166 (1986). https://doi.org/10.1007/BF01753417
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DOI: https://doi.org/10.1007/BF01753417