Tomographic 3D Reconstruction of Quick-Frozen, Ca2+-Activated Contracting Insect Flight Muscle

Motor actions of myosin were directly visualized by electron tomography of insect flight muscle quick-frozen during contraction. In 3D images, active cross-bridges are usually single myosin heads, bound preferentially to actin target zones sited midway between troponins. Active attached bridges (approximately 30% of all heads) depart markedly in axial and azimuthal angles from Rayment's rigor acto-S1 model, one-third requiring motor domain (MD) tilting on actin, and two-thirds keeping rigor contact with actin while the light chain domain (LCD) tilts axially from approximately 105 degrees to approximately 70 degrees. The results suggest the MD tilts and slews on actin from weak to strong binding, followed by swinging of the LCD through an approximately 35 degrees axial angle, giving an approximately 13 nm interaction distance and an approximately 4-6 nm working stroke.

[1]  T. Doyle,et al.  Nonspecific weak actomyosin interactions: relocation of charged residues in subdomain 1 of actin does not alter actomyosin function. , 1999, Biochemistry.

[2]  E. Homsher,et al.  Reversal of the cross‐bridge force‐generating transition by photogeneration of phosphate in rabbit psoas muscle fibres. , 1992, The Journal of physiology.

[3]  M. Reedy,et al.  Tomographic Three-dimensional Reconstruction of Insect Flight Muscle Partially Relaxed by AMPPNP and Ethylene Glycol , 1997, The Journal of cell biology.

[4]  Malcolm Irving,et al.  Tilting of the light-chain region of myosin during step length changes and active force generation in skeletal muscle , 1995, Nature.

[5]  R. Cooke,et al.  Actomyosin interaction in striated muscle. , 1997, Physiological reviews.

[6]  James D. Jontes,et al.  A 32° tail swing in brush border myosin I on ADP release , 1995, Nature.

[7]  K. Holmes,et al.  Muscle proteins--their actions and interactions. , 1996, Current opinion in structural biology.

[8]  M. Irving,et al.  Fluorescence polarization transients from rhodamine isomers on the myosin regulatory light chain in skeletal muscle fibers. , 1998, Biophysical journal.

[9]  G. Piazzesi,et al.  Elastic bending and active tilting of myosin heads during muscle contraction , 1998, Nature.

[10]  A. Houdusse,et al.  Atomic Structure of Scallop Myosin Subfragment S1 Complexed with MgADP A Novel Conformation of the Myosin Head , 1999, Cell.

[11]  T. Irving,et al.  X-ray diffraction indicates that active cross-bridges bind to actin target zones in insect flight muscle. , 1998, Biophysical journal.

[12]  Michael Whittaker,et al.  A 35-Å movement of smooth muscle myosin on ADP release , 1995, Nature.

[13]  I. Rayment,et al.  Structural studies on myosin II: Communication between distant protein domains , 1997, BioEssays : news and reviews in molecular, cellular and developmental biology.

[14]  M. Ferenczi,et al.  Structural changes in the actin-myosin cross-bridges associated with force generation induced by temperature jump in permeabilized frog muscle fibers. , 1999, Biophysical journal.

[15]  W. Kabsch,et al.  Atomic model of the actin filament , 1990, Nature.

[16]  J. Squire,et al.  The 4-stranded helical arrangement of myosin heads on insect (Lethocerus) flight muscle thick filaments , 1991 .

[17]  M. Irving,et al.  Dynamic measurement of myosin light-chain-domain tilt and twist in muscle contraction , 1999, Nature.

[18]  John M. Squire.  Molecular mechanisms in muscular contraction , 1983, Trends in Neurosciences.

[19]  R A Milligan,et al.  Structure of the actin-myosin complex and its implications for muscle contraction. , 1993, Science.

[20]  B. Brenner.  Muscle Mechanics and Biochemical Kinetics , 1990 .

[21]  M. Reedy,et al.  Two attached non-rigor crossbridge forms in insect flight muscle. , 1988, Journal of molecular biology.

[22]  Bernd Heinrich,et al.  The Thermal Warriors , 1996 .

[23]  V. Barnett,et al.  Resolution of three structural states of spin-labeled myosin in contracting muscle. , 1995, Biophysical journal.

[24]  M. Walker,et al.  Observation of transient disorder during myosin subfragment-1 binding to actin by stopped-flow fluorescence and millisecond time resolution electron cryomicroscopy: evidence that the start of the crossbridge power stroke in muscle has variable geometry. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[25]  C. Franzini-armstrong,et al.  Structure and periodicities of cross-bridges in relaxation, in rigor, and during contractions initiated by photolysis of caged Ca2+. , 1996, Biophysical journal.

[26]  R. T. Tregear,et al.  Movement and force produced by a single myosin head , 1995, Nature.

[27]  K A Taylor,et al.  Three-dimensional distortion correction applied to tomographic reconstructions of sectioned crystals. , 1996, Ultramicroscopy.

[28]  T. Wendt,et al.  Structure of the Lethocerus troponin-tropomyosin complex as determined by electron microscopy. , 1997, Journal of structural biology.

[29]  Experiments on rigor crossbridge action and filament sliding in insect flight muscle. , 1993, Advances in experimental medicine and biology.

[30]  K A Taylor,et al.  The use of electron tomography for structural analysis of disordered protein arrays. , 1997, Journal of structural biology.

[31]  J. Squire,et al.  Evidence for structurally different attached states of myosin cross-bridges on actin during contraction of fish muscle. , 1992, Biophysical journal.

[32]  C. Franzini-armstrong,et al.  Structural changes in muscle crossbridges accompanying force generation , 1994, The Journal of cell biology.

[33]  Roberto Dominguez,et al.  Crystal Structure of a Vertebrate Smooth Muscle Myosin Motor Domain and Its Complex with the Essential Light Chain Visualization of the Pre–Power Stroke State , 1998, Cell.

[34]  M. Reedy.  Ultrastructure of insect flight muscle. I. Screw sense and structural grouping in the rigor cross-bridge lattice. , 1968, Journal of molecular biology.

[35]  D A Winkelmann,et al.  Three-dimensional structure of myosin subfragment-1: a molecular motor. , 1993, Science.

[36]  Kenneth A. Taylor,et al.  Electron Tomography of Insect Flight Muscle in Rigor and AMPPNP at 23°C , 1996 .

[37]  M. Ferenczi,et al.  Muscle force is generated by myosin heads stereospecifically attached to actin , 1997, Nature.

[38]  J. Zou,et al.  Improved methods for building protein models in electron density maps and the location of errors in these models. , 1991, Acta crystallographica. Section A, Foundations of crystallography.

[39]  Independent mobility of catalytic and regulatory domains of myosin heads. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[40]  M. Geeves,et al.  Cooperativity between the two heads of rabbit skeletal muscle heavy meromyosin in binding to actin. , 1998, Biophysical journal.

[41]  Kenneth A. Taylor,et al.  Three-dimensional Structure of Nucleotide-bearing Crossbridgesin Situ: Oblique Section Reconstruction of Insect Flight Muscle in AMPPNP at 23°C , 1996 .

[42]  G. Piazzesi,et al.  Elastic distortion of myosin heads and repriming of the working stroke in muscle , 1995, Nature.

[43]  G. Phillips,et al.  Troponin and its interactions with tropomyosin. An electron microscope study. , 1982, Journal of molecular biology.

[44]  M. Reedy,et al.  Gold/Fab immuno electron microscopy localization of troponin H and troponin T in Lethocerus flight muscle. , 1994, Journal of molecular biology.

[45]  M. Reedy,et al.  Rigor crossbridge structure in tilted single filament layers and flared-X formations from insect flight muscle. , 1985, Journal of molecular biology.

[46]  Y. Goldman,et al.  Wag the Tail: Structural Dynamics of Actomyosin , 1998, Cell.