Skip to main content
NCBI home page
Biochemical Journal logoLink to Biochemical Journal
. 1986 Jan 1;233(1):173–177. doi: 10.1042/bj2330173

The kinetics of bivalent metal ion dissociation from myosin subfragments.

A J Bennett, C R Bagshaw
PMCID: PMC1153000  PMID: 3006656

Abstract

Bivalent metal ions have multiple roles in subunit association and ATPase regulation in scallop adductor-muscle myosin. To help elucidate these functions, the rates of Ca2+ and Mg2+ dissociation from the non-specific high-affinity sites on the regulatory light chains were measured and compared with those of rabbit skeletal-muscle myosin subfragments. Ca2+ dissociation had a rate constant of about 0.7 s-1 in both species, as measured by the time course of the pH change on EDTA addition. Mg2+ dissociation had a rate constant of 0.05 s-1, as monitored by its displacement with the paramagnetic Mn2+ ion. It is concluded that the exchange between Ca2+ and Mg2+ at the non-specific site, on excitation of both skeletal and adductor muscles, is too slow to contribute to the activation itself. The release of bivalent metal ions from the non-specific site is, however, the first step in release of the scallop regulatory light chain (Bennett & Bagshaw (1986) Biochem. J. 233, 179-186). In scallop myosin additional specific sites are present, which can bind Ca2+ rapidly, to effect activation of the ATPase. In the course of this work, Ca2+ dissociation from EGTA was studied as a model system. This gave rates of 1 s-1 and 0.3 s-1 at pH 7.0 and pH 8.0 respectively.

Full text

PDF
173

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bagshaw C. R. Divalent metal ion binding and subunit interactions in myosins: a critical review. J Muscle Res Cell Motil. 1980 Sep;1(3):255–277. doi: 10.1007/BF00711931. [DOI] [PubMed] [Google Scholar]
  2. Bagshaw C. R., Kendrick-Jones J. Characterization of homologous divalent metal ion binding sites of vertebrate and molluscan myosins using electron paramagnetic resonance spectroscopy. J Mol Biol. 1979 May 25;130(3):317–336. doi: 10.1016/0022-2836(79)90544-8. [DOI] [PubMed] [Google Scholar]
  3. Bagshaw C. R., Kendrick-Jones J. Identification of the divalent metal ion binding domain of myosin regulatory light chains using spin-labelling techniques. J Mol Biol. 1980 Jul 5;140(3):411–433. doi: 10.1016/0022-2836(80)90392-7. [DOI] [PubMed] [Google Scholar]
  4. Bagshaw C. R. On the location of the divalent metal binding sites and the light chain subunits of vertebrate myosin. Biochemistry. 1977 Jan 11;16(1):59–67. doi: 10.1021/bi00620a010. [DOI] [PubMed] [Google Scholar]
  5. Bagshaw C. R., Reed G. H. The significance of the slow dissociation of divalent metal ions from myosin 'regulatory' light chains. FEBS Lett. 1977 Sep 15;81(2):386–390. doi: 10.1016/0014-5793(77)80560-7. [DOI] [PubMed] [Google Scholar]
  6. Bagshow C. R., Reed G. H. Investigations of equilibrium complexes of myoxin subfragment 1 with the manganous ion and adenosine diphosphate using magnetic resonance techniques. J Biol Chem. 1976 Apr 10;251(7):1975–1983. [PubMed] [Google Scholar]
  7. Bennett A. J., Bagshaw C. R. The mechanism of regulatory light chain dissociation from scallop myosin. Biochem J. 1986 Jan 1;233(1):179–186. doi: 10.1042/bj2330179. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Chantler P. D., Szent-Györgyi A. G. Regulatory light-chains and scallop myosin. Full dissociation, reversibility and co-operative effects. J Mol Biol. 1980 Apr 15;138(3):473–492. doi: 10.1016/s0022-2836(80)80013-1. [DOI] [PubMed] [Google Scholar]
  9. Konno K., Arai K., Watanabe S. Fluorescence intensity and UV absorption changes accompanying dissociation and association of regulatory light chain of scallop adductor myosin. J Biochem. 1983 Oct;94(4):1061–1066. doi: 10.1093/oxfordjournals.jbchem.a134448. [DOI] [PubMed] [Google Scholar]
  10. Margossian S. S., Lowey S., Barshop B. Effect of DTNB light chain on the interaction of vertebrate skeletal myosin with actin. Nature. 1975 Nov 13;258(5531):163–166. doi: 10.1038/258163a0. [DOI] [PubMed] [Google Scholar]
  11. Persechini A., Rowe A. J. Modulation of myosin filament conformation by physiological levels of divalent cation. J Mol Biol. 1984 Jan 5;172(1):23–39. doi: 10.1016/0022-2836(84)90412-1. [DOI] [PubMed] [Google Scholar]
  12. Smith P. D., Liesegang G. W., Berger R. L., Czerlinski G., Podolsky R. J. A stopped-flow investigation of calcium ion binding by ethylene glycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid. Anal Biochem. 1984 Nov 15;143(1):188–195. doi: 10.1016/0003-2697(84)90575-x. [DOI] [PubMed] [Google Scholar]
  13. Stafford W. F., 3rd, Szentkiralyi E. M., Szent-Györgyi A. G. Regulatory properties of single-headed fragments of scallop myosin. Biochemistry. 1979 Nov 27;18(24):5273–5280. doi: 10.1021/bi00591a002. [DOI] [PubMed] [Google Scholar]
  14. Szent-Györgyi A. G., Szentkiralyi E. M., Kendrick-Jonas J. The light chains of scallop myosin as regulatory subunits. J Mol Biol. 1973 Feb 25;74(2):179–203. doi: 10.1016/0022-2836(73)90106-x. [DOI] [PubMed] [Google Scholar]
  15. Weeds A. G., Taylor R. S. Separation of subfragment-1 isoenzymes from rabbit skeletal muscle myosin. Nature. 1975 Sep 4;257(5521):54–56. doi: 10.1038/257054a0. [DOI] [PubMed] [Google Scholar]
  16. Wells C., Bagshaw C. R. Calcium regulation of molluscan myosin ATPase in the absence of actin. Nature. 1985 Feb 21;313(6004):696–697. doi: 10.1038/313696a0. [DOI] [PubMed] [Google Scholar]
  17. Wells C., Bagshaw C. R. Segmental flexibility and head-head interaction in scallop myosin. A study using saturation transfer electron paramagnetic resonance spectroscopy. J Mol Biol. 1983 Feb 15;164(1):137–157. doi: 10.1016/0022-2836(83)90090-6. [DOI] [PubMed] [Google Scholar]
  18. Wells C., Warriner K. E., Bagshaw C. R. Fluorescence studies on the nucleotide- and Ca2+-binding domains of molluscan myosin. Biochem J. 1985 Oct 1;231(1):31–38. doi: 10.1042/bj2310031. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Biochemical Journal are provided here courtesy of The Biochemical Society

RESOURCES