Skip to main content
NCBI home page
Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1994 Feb 1;91(3):937–941. doi: 10.1073/pnas.91.3.937

Determination of spin-label orientation within the myosin head.

P G Fajer 1
PMCID: PMC521428  PMID: 8302871

Abstract

Current methods of analyzing EPR spectra of spin-labeled muscle fibers allow the determination of spin-label orientation within the fiber, rather than the orientation of the myosin head itself. In order to describe the orientational distribution of spin labeled myosin heads within the muscle fibers, the orientation of the spin label within the myosin head must be known. The iodoacetamide label orientation in the myosin head was determined to be (16.8 degrees, 28.3 degrees, 4.2 degrees) or (16.6 degrees, 72.0 degrees, 4.3 degrees). These Eulerian angles were obtained from the analysis of EPR spectra of fibers decorated with labeled myosin heads in the absence of ATP, with the assumption that the head's tilt angle is 40 degrees, as observed in a recent EM study [Pollard, T., Bhandari, D., Maupin, P., Wachsstock, D., Weeds, A. & Zot, H. (1993) Biophys. J. 64, 454-471]. Knowledge of spin-label orientation will allow for quantitative determination of myosin head orientation in the various states of the contractile cycle.

Full text

PDF
937

Images in this article

938Image
on p.938
939Image
on p.939
941Image
on p.941

Selected References

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

  1. Ajtai K., Burghardt T. P. Observation of two orientations from rigor cross-bridges in glycerinated muscle fibers. Biochemistry. 1986 Oct 7;25(20):6203–6207. doi: 10.1021/bi00368a055. [DOI] [PubMed] [Google Scholar]
  2. Burghardt T. P., French A. R. Reconstruction of the probe angular distribution from a series of electron spin resonance spectra of tilted oriented samples. Biophys J. 1989 Sep;56(3):525–534. doi: 10.1016/S0006-3495(89)82699-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Craig R., Szent-Györgyi A. G., Beese L., Flicker P., Vibert P., Cohen C. Electron microscopy of thin filaments decorated with a Ca2+-regulated myosin. J Mol Biol. 1980 Jun 15;140(1):35–55. doi: 10.1016/0022-2836(80)90355-1. [DOI] [PubMed] [Google Scholar]
  4. Fajer P. G., Fajer E. A., Brunsvold N. J., Thomas D. D. Effects of AMPPNP on the orientation and rotational dynamics of spin-labeled muscle cross-bridges. Biophys J. 1988 Apr;53(4):513–524. doi: 10.1016/S0006-3495(88)83131-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Fajer P. G., Fajer E. A., Matta J. J., Thomas D. D. Effect of ADP on the orientation of spin-labeled myosin heads in muscle fibers: a high-resolution study with deuterated spin labels. Biochemistry. 1990 Jun 19;29(24):5865–5871. doi: 10.1021/bi00476a031. [DOI] [PubMed] [Google Scholar]
  6. Huxley H. E. The mechanism of muscular contraction. Science. 1969 Jun 20;164(3886):1356–1365. doi: 10.1126/science.164.3886.1356. [DOI] [PubMed] [Google Scholar]
  7. Mailer C., Taylor C. P. Electron paramagnetic resonance study of single crystals of horse heart ferricytochrome c at 4.2 degrees K. Can J Biochem. 1972 Oct;50(10):1048–1055. doi: 10.1139/o72-145. [DOI] [PubMed] [Google Scholar]
  8. McFarland B. G., McConnell H. M. Bent fatty acid chains in lecithin bilayers. Proc Natl Acad Sci U S A. 1971 Jun;68(6):1274–1278. doi: 10.1073/pnas.68.6.1274. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Mendelson R. A., Wilson M. G. Three-dimensional disorder of dipolar probes in a helical array. Application to muscle cross-bridges. Biophys J. 1982 Aug;39(2):221–227. doi: 10.1016/S0006-3495(82)84511-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Morales M. F. Calculation of the polarized fluorescence from a labeled muscle fiber. Proc Natl Acad Sci U S A. 1984 Jan;81(1):145–149. doi: 10.1073/pnas.81.1.145. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Pollard T. D., Bhandari D., Maupin P., Wachsstock D., Weeds A. G., Zot H. G. Direct visualization by electron microscopy of the weakly bound intermediates in the actomyosin adenosine triphosphatase cycle. Biophys J. 1993 Feb;64(2):454–471. doi: 10.1016/S0006-3495(93)81387-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Rayment I., Rypniewski W. R., Schmidt-Bäse K., Smith R., Tomchick D. R., Benning M. M., Winkelmann D. A., Wesenberg G., Holden H. M. Three-dimensional structure of myosin subfragment-1: a molecular motor. Science. 1993 Jul 2;261(5117):50–58. doi: 10.1126/science.8316857. [DOI] [PubMed] [Google Scholar]
  13. Reedy M. K., Holmes K. C., Tregear R. T. Induced changes in orientation of the cross-bridges of glycerinated insect flight muscle. Nature. 1965 Sep 18;207(5003):1276–1280. doi: 10.1038/2071276a0. [DOI] [PubMed] [Google Scholar]
  14. STRYER L., KENDREW J. C., WATSON H. C. THE MODE OF ATTACHMENT OF THE AZIDE ION TO SPERM WHALE METMYOGLOBIN. J Mol Biol. 1964 Jan;8:96–104. doi: 10.1016/s0022-2836(64)80152-2. [DOI] [PubMed] [Google Scholar]
  15. Thomas D. D., Cooke R. Orientation of spin-labeled myosin heads in glycerinated muscle fibers. Biophys J. 1980 Dec;32(3):891–906. doi: 10.1016/S0006-3495(80)85024-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Winkelmann D. A., Baker T. S., Rayment I. Three-dimensional structure of myosin subfragment-1 from electron microscopy of sectioned crystals. J Cell Biol. 1991 Aug;114(4):701–713. doi: 10.1083/jcb.114.4.701. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

RESOURCES