CS35: Models for skeletal muscle contraction

1. NTP metabolism and transduction CS35: Models for skeletal muscle contraction Biochemistry 655 6 April 2011

2. Goals • Understand the role of fibre diffraction in modeling skeletal muscle • The equatorial pattern ([1,0] and [1,1] reflections) • The meridional pattern (axial repeats) • Symmetry mismatches • The time-dependence of events involved in contraction • Assembling actomyosin from crystal structures • Multiple states of myosin • Problems associated with the fitting of actin crystal structures (Page, Schutt) • The actin helix-ribbon transition • Possible descent of myosin and actin from class I, II aaRS

14. Actin conformational changes

16. Internal rigid body mechanics of Actin

17. Hinge-bending Shear Rigid-bodies Actin dynamics

19. Motif 1 is “domain swapped” in HSP70 and SerRS Motif 2 superimposes on the HSP70 ATP-binding motif Strand-loop-helix that fixes thea-NH2 group in Class II aaRS also in HSP70 Class I & II tertiary scaffolds can be coded as SASORFs!!Carter & Duax, Molecular Cell, (2002) 10:705-708 Myosin? Actin?

20. NTP metabolism and transduction CS36: Energy transduction revisited: a retrospective and summary Biochemistry 655 18 November 2009

21. Goals • Discuss the allosteric behavior of myosin (Shriver & Sykes). • Multiple energy wells • Different ligand affinities • Recite the abstract from Marsten, et al. • Understand the meaning of all terms! • Describe the effect of AMPPNP • Is it really non-hydrolyzable? • If so, how to explain its effects on glycerol extracted muscle? • Walking through the cross-bridge cycle in reverse. • Understand why the “series elastic component” is necessary. • Terrill Hill’s model • Efficiency of energy conversion • The actin helix-ribbon transition (Schutt)

23. ATP ADP + Pi Myosin is an allosteric enzyme

24. Deconstruct this sentence!

33. Chemomechanical coupling