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The structural basis of the cross-bridge cycle

The structural basis of the cross-bridge cycle. DECORATED ACTIN was the first em reconstruction Moore, Huxley, and DeRosier 1970 J. Mol Biol. Reconstruction by filtered least squares. Projection every 1° (181 projections) Number of observational equations is 161 x 181=29141

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The structural basis of the cross-bridge cycle

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  1. The structural basis of the cross-bridge cycle

  2. DECORATED ACTIN was the first em reconstruction Moore, Huxley, and DeRosier 1970 J. Mol Biol.

  3. Reconstruction by filtered least squares

  4. Projection every 1° (181 projections) Number of observational equations is 161 x 181=29141 Order of normal matrix 17645. Problem should be well determined

  5. Oops!!

  6. Case 2. Projection every 3°, not enough data to invert the normal matrix. How much data is there? To determine the rank of a positive (semi) definite matrix we determine its eigenvalue spectrum

  7. Decorated actin at 13Å resolving power calculated by filtered least squares

  8. Electron cryo-microscopy (of decorated actin) shows how strong binding of myosin to actin releases nucleotide Holmes, Angert, Kull, Jahn, Schroeder (2003) Nature 425, 423-427

  9. Four sub-domain refinement

  10. The cross-bridge cycle As revealed by crystallography

  11. Geeves, M.A. & Holmes, K.C. (2005) The molecular mechanism of muscle contraction Adv Protein Chem 71, 161-93

  12. Lymn & Taylor, 1971

  13. The myosin motor domain must move the lever arm from pre- to post- power stroke. It must bind to actin strongly or weakly Both functions are controlled by ATP binding and hydrolysis

  14. Crystallography on the motor domain (particularly Dictyostelium Myosin 2) shows two conformations of myosin: lever UP and lever DOWN

  15. Diskussionsthemen • Nennen Sie die Hauptthesen, über die Sie sprechen werden.

  16. Thema 1 • Details über das Thema • Argumente und Beispiele • Warum ist das Thema für Ihr Publikum von Bedeutung?

  17. switch 1

  18. Fischer et al (2005) PNAS102 6873-8

  19. Fischer et al (2005) PNAS102 6873-8

  20. Weak and Strong Binding

  21. Coureux, P. D.Wells, A. L.Menetrey, J.Yengo, C. M.Morris, C. A.Sweeney, H. L.Houdusse, A. (2003) A structural state of the myosin V motor without bound nucleotide Nature 425 419-23

  22. Rayment_chicken

  23. Upper/lower 50K fitted

  24. Myo 5

  25. ?

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