Summary
Troponin-tropomyosin-regulated myofibrils show a significant increase in ATPase activity and contract in the absence of calcium when the ATP concentration falls significantly below the saturation level. By contrast, the ATPase of the myosin-regulated myofibrils of scallop striated muscle was not activated in the absence of calcium when the ATP concentration was lowered to 10 mm. Nevertheless, a very small fraction of crossbridges were active at 10 mm ATP resulting in very slow myofibrillar shortening. In contrast to the behaviour of rabbit contractile proteins there was no correlation between myofibrillar shortening and ATP induced turbidity changes of actomyosin taken from scallop.
Similar content being viewed by others
References
Adelstein, R. S. &Eisenberg, E. (1980) Regulation and kinetics of the actin-myosin-ATP interaction.A. Rev. Biochem. 49, 921–56.
Bremel, R. D. &Weber, A. Cooperation within actin filament in vertebrate skeletal muscle.Nature, New Biol. 238, 97–101.
Bremel, R. D., Murray, J. M. &Weber, A. (1972) Manifestations of cooperative behavior in the regulated actin filament during actin-activated ATP hydrolysis in the presence of calcium.Cold Spring Harbor Symp. quant. Biol. 37, 267–75.
Chantler, P. D. &Szent-Györgyi, A. G. (1980) Regulatory light-chains and scallop myosin: full dissociation, reversibility and co-operative effects.J. molec. Biol. 138, 473–92.
Chantler, P. D., Sellers, J. R. &Szent-Györgyi, A. G. (1981) Cooperativity in scallop myosin.Biochemistry 20, 210–16.
Ebashi, S., Endo, M. &Ohtsuki, I. (1969) Control of muscle contraction.Quart. Rev. Biophys. 2, 351–84.
Focant, B. &Huriaux, F. (1976) Light chains of carp and pike skeletal muscle myosins. Isolation and characterization of the most anodic light chain on alkaline pH electrophoresis.FEBS Lett. 65, 16–19.
Haselgrove, J. C. (1972) X-ray evidence for a conformational change in the actin-containing filaments of vertebrate striated muscle.Cold Spring Harbor Symp. quant. Biol. 37, 341–52.
Huxley, H. E. (1972) Structural changes in the actin- and myosin-containing filaments during contraction.Cold Spring Harbor Symp. quant. Biol. 37, 361–76.
Kendrick-Jones, J., Lehman, W. andSzent-Györgyi, A. (1970) Regulation in molluscan muscles.J. molec. Biol. 54, 313–26.
Maruyama, K. &Weber, A. (1972) Binding of adenosine triphosphate to myofibrils during contraction and relaxation.Biochemistry 11, 2990–8.
Murray, J. M., Weber, A. &Knox, M. K. (1981) Myosin subfragment 1 binding to relaxed actin filaments and steric model of relaxationBiochemistry 20, 641–9.
Sanger, J. W. (1971) Sarcoplasmic reticulum in the cross-striated adductor muscle of the bay scallop,Aequipecten irradians.Z. Zellforsch. 118, 156–61.
Simmons, R. M. &Szent-Györgyi, A. G. (1985) A mechanical study of regulation in the striated adductor muscle of the scallop.J. Physiol, Lond. 358, 47–64.
Szent-Györgyi, A. G., Szentkiralyi, E. M. &Kendrickjones, J. (1973) The light chains of scallop myosin as regulatory subunits.J. molec. Biol. 74, 179–203.
Tanaka, H. &Tanaka, M. (1979) Dependence of tension development on calcium and magnesium adenosinetriphosphates in chemically skinned molluscan smooth muscle fibers.J. Biochem, Tokyo 85, 713–17.
Toyo-Oka, T. (1979) Effects of various concentrations of MgATP on the superprecipitation and ATPase activity of scallop striated muscle myosin B.J. Biochem, Tokyo 85, 871–7.
Trueblood, C. E., Walsh, T. P. &Weber, A. (1982) Is the steric model of tropomyosin action valid? InBasic Biology of Muscles: A Comparative Approach (edited byTwarog, B. M., Levine, R. J. C. andDewey, M. M.), pp. 223–241. New York: Raven Press.
Weber, A., Herz, R. &Reiss, I. (1963) On the mechanism of the relaxing effect of fragmented sarcoplasmic reticulum.J. gen. Physiol. 46, 679–702.
Weber, A., Herz, R. &Reiss, I. (1964) The regulation of myofibrillar activity by calcium.Proc. R. Soc. Ser. B. 161, 489–501.
Weber, A. &Murray, J. M. (1973) Molecular control mechanisms in muscle contraction.Physiol. Rev. 53, 612–73.
Weber, K. &Osborn, M. (1969) The reliability of molecular weight determinations by dodecyl sulfate-polyacrylamide gel electrophoresis.J. biol. Chem. 244, 4406–12.
Wells, C. &Bagshaw, C. R. (1984) The Ca2+ sensitivity of the actin-activated ATPase of scallop heavy meromyosin.FEBS Lett. 168, 260–4.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Knox, M.K., Szent-Györgyi, A.G., Trueblood, C.E. et al. The effect of low ATP concentrations on relaxation in the myosin regulated myofibrils from scallop. J Muscle Res Cell Motil 7, 110–114 (1986). https://doi.org/10.1007/BF01753411
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01753411