Location of Repository

Dynamics of actomyosin interactions in relation to the cross-bridge cycle

By Wei Zeng, Paul B. Conibear, Jane L. Dickens, Ruth A. Cowie, Stuart Wakelin, András Málnási-Csizmadia and Clive R. Bagshaw


Transient kinetic measurements of the actomyosin ATPase provided the basis of the Lymn–Taylor model for the cross-bridge cycle, which underpins current models of contraction. Following the determination of the structure of the myosin motor domain, it has been possible to introduce probes at defined sites and resolve the steps in more detail. Probes have been introduced in the Dictyostelium myosin II motor domain via three routes: (i) single tryptophan residues at strategic locations throughout the motor domain; (ii) green fluorescent protein fusions at the N and C termini; and (iii) labelled cysteine residues engineered across the actin-binding cleft. These studies are interpreted with reference to motor domain crystal structures and suggest\ud that the tryptophan (W501) in the relay loop senses the lever arm position, which is controlled by the switch 2 open-to-closed transition at the active site. Actin has little effect on this process per se. A mechanism of product release is proposed in which actin has an indirect effect on the switch 2 and lever arm position to achieve mechanochemical coupling. Switch 1 closing appears to be a key step in the nucleotide-induced actin dissociation, while its opening is required for the subsequent activation of product release. This process has been probed with F239W and F242W substitutions in the switch 1 loop. The E706K mutation in skeletal myosin IIa is associated with a human myopathy. To simulate this disease we investigated the homologous mutation, E683K, in the Dictyostelium myosin motor domain

Publisher: Royal Society of London
Year: 2004
OAI identifier: oai:lra.le.ac.uk:2381/73

Suggested articles



  1. (2000). A FRET-based sensor reveals large ATP hydrolysisinduced conformational changes and three distinct states of the molecular motor myosin. doi
  2. (2003). A prism combination for near isotropic fluorescence excitation by total internal reflection. doi
  3. (2003). A structural model for actin-induced nucleotide release in myosin. doi
  4. (2003). A structural state of the myosin V motor without bound nucleotide. doi
  5. (1997). Alanine scanning mutagenesis of the switch I region in the ATPase site of Dictyostelium discoideum myosin II. doi
  6. (2003). An actin-dependent conformational change in myosin. doi
  7. (2002). An asymmetry in the phosphate dependence of tension transients induced by length perturbation in mammalian (rabbit psoas) muscle fibres. doi
  8. (2002). Analysis of nucleotide binding to Dictyostelium myosin II motor domains containing a single tryptophan near the active site. doi
  9. (1998). ATPase kinetics of the Dictyostelium discoideum myosin II motor domain. doi
  10. (2000). Autosomal dominant myopathy: missense mutation (Glu-706 ! Lys) in the myosin heavy chain IIa gene. doi
  11. (1997). Dictyostelium discoideum myosin II: characterization of functional myosin motor fragments. doi
  12. (2003). Dictyostelium myosin II mutations that uncouple the converter swing and ATP hydrolysis cycle. doi
  13. (2002). Engineering Dictyostelium discoideum myosin II for the introduction of site-specific probes. doi
  14. (1980). Exchange between inorganic phosphate and adenosine 50-triphosphate in the medium by actomyosin subfragment 1.Biochemistry 19, doi
  15. (1988). Flexibility of the myosin heavy chain: direct evidence that the region containing SH1 and SH2 can move 10 A˚ under the influence of nucleotide binding. doi
  16. (1973). Fluorimetric studies on the influence of metal ions and chelators on the interaction between myosin and ATP. doi
  17. (1999). Functional characterisation of Dictyostelium myosin II with conserved tryptophanyl residue 501 mutated to tyrosine.Biol. doi
  18. (1978). Intermediate states of subfragment 1 and actosubfragment 1 ATPase: reevaluation of the mechanism. doi
  19. (1995). Is myosin a ‘back door’ enzyme?Biophys. doi
  20. (2000). Isolating and localizing ATP-sensitive tryptophan emission in skeletal myosin subfragment 1.Biochemistry 39, doi
  21. (1999). Kinetic analysis of Dictyostelium discoideum myosin motor domains with glycine-to-alanine mutations in the reactive thiol region. doi
  22. (1993). Kinetic characterization of a cytoplasmic myosin motor domain expressed in Dictyostelium discoideum. doi
  23. (2001). Kinetic resolution of a conformational transition and the ATP hydrolysis step using relaxation methods with a Dictyostelium myosin II mutant containing a single tryptophan residue. doi
  24. (1971). Mechanism of adenosine triphosphate hydrolysis by actomyosin. doi
  25. (1997). Muscle force is generated by myosin heads stereospecifically attached to actin. doi
  26. (1957). Muscle structure and theories of contraction. doi
  27. (1998). Mutational analysis of the switch II loop of Dictyostelium myosin II. doi
  28. (2003). Myosin cleft movement and its coupling to actomyosin dissociation. doi
  29. (2002). Myosin heavy chain IIa gene mutation E706K is pathogenic and its expression increases with age. doi
  30. (2000). On the tryptophan residue of smooth muscle myosin that responds to binding of nucleotide. doi
  31. (1975). Oxygen exchange in the g-phosphoryl group of protein-bound ATP during Mg2+-dependent adenosine triphosphatase activity of myosin. doi
  32. (2000). Past, present and future experiments on muscle. doi
  33. (1988). Protein fluorescence changes associated with ATP and adenosine 50-[c-thio]-triphosphate binding to skeletal muscle myosin subfragment 1 and actomyosin subfragment 1.Biochem. doi
  34. (2000). Resolution of conformational states of Dictyostelium myosin II motor domain using tryptophan (W501) mutants: implications for the open-closed transition identified by crystallography.Biochemistry 39, doi
  35. (1999). Sensitivity of the yellow variant of green fluorescent protein to halides and nitrate. doi
  36. (1954). Structural changes in muscle during contraction.Nature 173, doi
  37. (1999). Structural mechanism of muscle contraction. doi
  38. (1993). Structure of the actin–myosin complex and its implications for muscle contraction. doi
  39. (1996). Structure-function analysis of the motor domain of myosin.
  40. (1998). Swing of the lever arm of a myosin motor at the isomerization and phosphate-release steps.
  41. (1974). Synthesis of ATP from ADP and inorganic phosphate at the myosinsubfragment 1 active site. doi
  42. (1977). The binding constant of ATP to myosin S1 fragment. doi
  43. (2004). The effect of F-actin on the relay helix position of myosin II, as revealed by tryptophan fluorescence, and its implications for mechanochemical coupling. doi
  44. (1974). The magnesium ion-dependent adenosine triphosphatase of myosin. Twostep processes of adenosine triphosphate association and adenosine diphosphate dissociation. doi
  45. (1969). The mechanism of muscular contraction. doi
  46. (1982). The reactive SH1 and SH2 cysteines in myosin subfragment 1 are cross-linked at similar rates with reagents of different length. doi
  47. (2000). The structural basis of muscle contraction. doi
  48. (2004). The structure of the rigor complex and its implications for the power stroke.
  49. (2003). The working stroke upon myosin-nucleotide complexes binding to actin. doi
  50. (1999). Thiol-specific cross-linkers of variable length reveal a similar separation of SH1 and SH2 in myosin subfragment 1 in the presence and absence of MgADP. doi
  51. (2000). Three conformational states of scallop myosin S1. doi
  52. (1993). Three-dimensional structure of myosin subfragment-1: a molecular motor. doi
  53. (1972). Transient kinetic studies of the Mg2+-dependent ATPase of myosin and its proteolytic subfragments. Cold Spring Harbor Symp. doi
  54. (1982). Transient kinetics of adenosine 50-diphosphate and adenosine 50-(b, c-imidotriphosphate) binding to subfragment 1 and actosubfragment 1.Biochemistry 21, 1284–1294.Phil. doi
  55. (1977). Transient phase of adenosine triphosphate hydrolysis by myosin, heavy meromyosin, and subfragment 1. doi
  56. (2000). Tryptophan 512 is sensitive to conformational changes in the rigid relay loop of smooth muscle myosin during the MgATPase cycle. doi
  57. (2004). Using optical tweezers to relate the chemical and mechanical cross-bridge cycles. doi
  58. (1996). X-ray structure of the magnesium(II).ADP.vanadate complex of the Dictyostelium discoideum myosin motor domain to 1.9 A˚ resolution. doi
  59. (2000). X-ray structures of the apo and MgATPbound states of Dictyostelium discoideum myosin motor domain. doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.