Abstract
The program MusLABEL has been devised as a simple aid both in understanding the origin and appearance of fibre diffraction patterns from helical structures and also to simulate the structure and some features of the diffraction patterns from striated muscles and their filament components. Helices are common as preferred conformations in both natural and synthetic macromolecules (e.g. DNA, α -helices, polysaccharides, synthetic polymers), and they also occur frequently in extended macromolecular aggregates (e.g. actin filaments, myosin filaments, microtubules, amyloid filaments etc). For this reason, a simple way of visualising the kinds of diffraction patterns that these filament structures can give, particularly for the actin and myosin filaments in muscle, can have educational value and can also be useful as a quick means of evaluating possible symmetries in structural interpretations of diffraction data before embarking on full helical diffraction analysis. A feature of the MusLABEL program is that, when a particular kind of A-band lattice has been set up, for example for vertebrate striated muscle or insect flight muscle, additional parameters can be defined both to describe the limits to the azimuthal and axial ranges over which a myosin head can search for an actin binding site and also to describe the size and position of an actin `target area' assuming that the azimuthal position of an actin monomer has a large effect in determining whether or not a myosin head can bind to it. By this means the effects of lattice geometry on head attachment can be explored and the diffraction effects of specific labelling patterns on actin can be calculated and simulated. The MusLABEL program, running under Microsoft Windows, is available free on the CCP13 website (www.ccp13.ac.uk) where further documentation is given.
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AL-Khayat HA, Hudson L, Reedy MK, Irving TC and Squire JM (2004) Modelling oriented macromolecular assemblies from low-angle X-ray fibre diffraction data with the program MOVIE: insect flight muscle as an example. Fibre Diffraction Review (www.fibrediffractionreview.org) 12: 50–60.
Arnott S and Wonacott AJ (1966) Atomic co-ordinates for an α-helix: refinement of the crystal structure of α-poly-l-alanine. J Mol Biol 21: 371–383.
Chandrasekaran R and Stubbs G (2001) Fibre diffraction. In Intl. Tables for Crystallog. Vol. F. (pp. 444–450), Kluwer, Dordrecht/Boston/London.
Cochran W, Crick FHC and Vand V (1952) The structure of synthetic polypeptides. I. The transform of atoms in a helix. Acta Crystallographica 5: 581–586.
Elliott GF, Lowy J and Millman BM (1965) X-ray diffraction from living striated muscle during contraction. Nature 206: 1357–1358.
Elliott GF, Lowy J and Millman BM (1967) Low-angle X-ray diffraction from living striated muscle during contraction. J Mol Biol 25: 31–45.
Harford JJ and Squire JM (1997) Time-resolved studies of muscle using synchrotron radiation. Rep Prog Phys 60: 1723–1787.
Holmes KC and Blow DM (1965) Use of X-ray Diffraction in the Study of Protein and Nucleic Acid Structure. Interscience Publishing Company.
Holmes KC, Tregear RT and Barrington-Leigh J (1980) Interpretation of the low-angle X-ray diffraction from insect flight muscle in rigor. Proc Roy Soc B 207: 13–33.
Hudson L, IHarford JJ, Denny RJ and Squire JM (1997) Myosin head configurations in relaxed fish muscle: resting state myosin heads swing axially by 150 Å or turn upside down to reach rigor. J Mol Biol 273: 440–455.
Holmes KC, Popp D, Gebhard W and Kabsch W (1990) Atomic model of the actin filament. Nature 347: 44–49.
Huxley HE and Brown W (1967) The low-angle X-ray diagram of vertebrate striated muscle and its behaviour during contraction and rigor. J Mol Biol 30: 383–434.
Huxley HE, Brown W and Holmes KC (1965) Constancy of spacings in frog sartorius muscle during contraction. Nature 206: 1358.
Knupp C and Squire JM (2004) HELIX: a helical diffraction simulation program. J Appl Cryst 37: 832–835.
Koubassova NA and Tsaturyan AK (2002) Direct modelling of X-ray diffraction pattern from skeletal muscle in rigor. Biophys J 83: 1082–1097.
Luther PK and Squire JM (1980) Three-dimensional structure of the vertebrate muscle A-band II: the myosin filament superlattice. J Mol Biol 141: 409–439.
Luther PK, Munro PMG and Squire JM (1981) Three-dimensional structure of the vertebrate muscle A-band III: M-region structure and myosin filament symmetry. J Mol Biol 151: 703–730.
Okada K, Noguchi K, Okuyama K and Arnott S (2003) WinLALS for a linked-atom least-square refinement program for helical polymers on Windows PCs. Comptl Biol & Chem 27: 265–285.
Pask H, Jones KL, Luther PK and Squire JM (1994) M-band Structure, M-bridge interactions and contraction speed in vertebrate cardiac muscles. J Mus Res Cell Motil 15: 633–645.
Squire JM (1972) General model of myosin filament structure II: myosin filaments and crossbridge interactions in vertebrate striated and insect flight muscles. J Mol Biol 72: 125–138.
Squire JM (1981) The Structural Basis of Muscular Contraction, Plenum Publishing Co., New York.
Squire JM (1992) Muscle filament lattices and stretch-activation: the match/mismatch model reassessed. J Musc Res Cell Motil 13: 183–189.
Squire JM (1997) Architecture and function in the muscle sarcomere. Curr Opin Struct Biol 7: 247–257.
Squire JM (2000) Fibre and muscle diffraction. In: Fanchon E, Geissler E, Hodeau L-L, Regnard J-R and Timmins P (eds) Structure and Dynamics of Biomolecules. pp. (272–301). Oxford University Press, Oxford, UK.
Squire JM (2003) Fibre diffraction review (www.fibrediffractionreview.org) 11: 3–4.
Squire JM and Harford JJ (1988) Actin filament organisation and myosin head labelling patterns in vertebrate skeletal muscles in the rigor and weak-binding states. J Mus Res Cell Motil 9: 344–358.
Squire JM, Knupp C, Roessle M, AL-Khayat HA, Irving TC, Eakins F, Mok NS, Harford JJ and Reedy MK (in press) X-ray diffraction studies of striated muscles. In: Sugi H (ed.) Puzzles of the Sliding Filament Mechanism. Advances in Experimental Medicine and Biology.
Wray JS (1979) Filament geometry and the activation of insect flight muscle. Nature 280: 325–326.
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Squire, J.M., Knupp, C. MusLABEL: a program to model striated muscle A-band lattices, to explore crossbridge interaction geometries and to simulate muscle diffraction patterns. J Muscle Res Cell Motil 25, 423–438 (2004). https://doi.org/10.1007/s10974-004-3147-0
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DOI: https://doi.org/10.1007/s10974-004-3147-0