The interaction of chromophoric nucleotides with subfragment 1 of myosin
- 1 April 1977
- journal article
- research article
- Published by Portland Press Ltd. in Biochemical Journal
- Vol. 163 (1), 15-29
- https://doi.org/10.1042/bj1630015
Abstract
The interaction of a series of chromophoric nucleotides derived from 6-mercapto-9-.beta.-ribofuranosylpurine [thioinosine (thioI)] and 2-amino-6-mercapto-9-.beta.-ribofuranosylpurine [thioguanosine (thioG)] with myosin subfragment 1 [S-1] isolated from rabbit skeletal muscle was investigated kinetically and spectroscopically. The Mg2+-dependent hydrolyses of thioITP and thioGTP were catalyzed by S-1 and probably proceed by a similar mechanism as for ATP hydrolysis, although with different rate constants; e.g., the binary thioGDP-protein complex only comprised 8% of the steady-state intermediate of the thioGTPase at 5.degree. C and pH 6.5. Long-lived analogues of intermediates of the thioGTPase were generated by using thioGTP(.gamma.S) [thioguanosine 5''-(3-thio)-triphosphate], thioGMP-P(NH)P (5''-thioguanylylimidodiphosphate) and thioGDP. The near-UV spectra of the thioguanosine nucleotides bound to S-1 were measured and showed that in all cases the purine ring was bound to the protein in a hydrophobic environment, although the pK of the purine thiol group only increased by 0.2-0.3. ThioGTP caused glycerinated rabbit psoas muscle to contract, but in contrast with thioITP was not able to relax muscle. The applications of these chromophoric nucleotides for investigating the mechanism of muscle contraction and other biological systems, particularly those involving guanosine nucleotide regulation, were discussed.This publication has 39 references indexed in Scilit:
- The bioenergetics of brown adipose tissue mitochondriaFEBS Letters, 1976
- ATP AnalogsPublished by Wiley ,1975
- Synthesis of ATP from ADP and Inorganic Phosphate at the Myosin‐Subfragment 1 Active SiteEuropean Journal of Biochemistry, 1974
- Fluorimetric studies on the influence of metal ions and chelators on the interaction between myosin and ATPFEBS Letters, 1973
- Conformational Differences in Myosin, II. Evidence for Differences in the Conformation Induced by Bound or Hydrolyzed Adenosine TriphosphateHoppe-Seyler´s Zeitschrift Für Physiologische Chemie, 1973
- Substructure of the myosin moleculeJournal of Molecular Biology, 1969
- Mechanical factors affecting the ATP ase activity of glycerol-extracted insect fibrillar flight muscleProceedings of the Royal Society of London. B. Biological Sciences, 1966
- Conversion of Mono- and Oligodeoxyribonucleotides to 5'-Triphosphates1Journal of the American Chemical Society, 1965
- Synthesis of nucleotide anhydrides by anion exchangeBiochimica et Biophysica Acta (BBA) - Specialized Section on Nucleic Acids and Related Subjects, 1964
- Studies on the structure of myosinJournal of Molecular Biology, 1962