Contrast transfer for frozen-hydrated specimens II. Amplitude contrast at very low frequencies

Abstract The contrast transfer properties of frozen-hydrated specimens were examined quantitatively for low spatial frequencies (1/350-1/160 A -1 ). Specimens used were tubular crystal of two membrane protiens, the acetylcholine receptor and calcium-ATPase. These specimens were found to behave as weak-phase-weak-amplitude objects. The contribution of amplitude contrast was 5.8% at 120 kV and 4.8% at 200 kV accelerating voltage. Combined with previous results, the level of amplitude contrast showed little dependence on the spatial frequency over the range examined so far (1/350-1/35 A -1 ).

[1]  D. DeRosier,et al.  Reconstruction of three-dimensional images from electron micrographs of structures with helical symmetry. , 1970, Journal of molecular biology.

[2]  D. Caspar,et al.  Tropomyosin: crystal structure, polymorphism and molecular interactions. , 1969, Journal of molecular biology.

[3]  G. Phillips,et al.  Structural studies of tropomyosin by cryoelectron microscopy and x-ray diffraction. , 1991, Biophysical journal.

[4]  R. Henderson,et al.  Molecular structure determination by electron microscopy of unstained crystalline specimens. , 1975, Journal of molecular biology.

[5]  M. Isaacson,et al.  Electronic and chemical analysis of fluoride interface structures at subnanometer spatial resolution , 1986 .

[6]  R A Milligan,et al.  Structural relationships of actin, myosin, and tropomyosin revealed by cryo-electron microscopy , 1987, The Journal of cell biology.

[7]  L. Castellani,et al.  Dimer ribbons in the three-dimensional structure of sarcoplasmic reticulum. , 1985, Journal of molecular biology.

[8]  C. Toyoshima On the use of holey grids in electron crystallography , 1989 .

[9]  A. Engel,et al.  Monte Carlo calculations of elastic and inelastic electron scattering in biological and plastic materials , 1984 .

[10]  W. Kabsch,et al.  Muscle proteins: actin , 1991 .

[11]  S. Fleischer,et al.  Isolation of sarcoplasmic reticulum by zonal centrifugation and purification of Ca 2+ -pump and Ca 2+ -binding proteins. , 1973, Biochimica et biophysica acta.

[12]  M. Whittaker,et al.  Molecular structure of F-actin and location of surface binding sites , 1990, Nature.

[13]  M. Radermacher,et al.  Determination of the phase of complex atomic scattering amplitudes from light-optical diffractograms of electron microscope images , 1982 .

[14]  L. Reimer Transmission Electron Microscopy: Physics of Image Formation and Microanalysis , 1989 .

[15]  J. Lepault,et al.  Structure of purple membrane from halobacterium halobium: recording, measurement and evaluation of electron micrographs at 3.5 Å resolution , 1986 .

[16]  Werner K¨hlbrandt,et al.  Three-dimensional structure of plant light-harvesting complex determined by electron crystallography , 1991, Nature.

[17]  A. Martonosi,et al.  Two-dimensional arrays of proteins in sarcoplasmic reticulum and purified Ca2+-ATPase vesicles treated with vanadate. , 1983, The Journal of biological chemistry.

[18]  A. Klug,et al.  Measurement and compensation of defocusing and aberrations by Fourier processing of electron micrographs , 1971 .

[19]  N. Unwin,et al.  Location of subunits within the acetylcholine receptor by electron image analysis of tubular crystals from Torpedo marmorata , 1987, The Journal of cell biology.

[20]  R. Henderson,et al.  Model for the structure of bacteriorhodopsin based on high-resolution electron cryo-microscopy. , 1990, Journal of molecular biology.

[21]  R A Crowther,et al.  Visualization of alpha-helices in tobacco mosaic virus by cryo-electron microscopy. , 1989, Journal of molecular biology.

[22]  N. Unwin,et al.  Ion channel of acetylcholine receptor reconstructed from images of postsynaptic membranes , 1988, Nature.

[23]  K. Taylor,et al.  Three-dimensional reconstruction of negatively stained crystals of the Ca2+-ATPase from muscle sarcoplasmic reticulum. , 1986, Journal of molecular biology.

[24]  J. Dubochet,et al.  Cryo-electron microscopy of vitrified specimens , 1988, Quarterly Reviews of Biophysics.

[25]  K. Gehring,et al.  Structural architecture of an outer membrane channel as determined by electron crystallography , 1991, Nature.

[26]  N. Unwin,et al.  Contrast transfer for frozen-hydrated specimens: determination from pairs of defocused images. , 1988, Ultramicroscopy.

[27]  N. Unwin,et al.  Three-dimensional structure of the acetylcholine receptor by cryoelectron microscopy and helical image reconstruction , 1990, The Journal of cell biology.

[28]  D. L. Misell On the validity of the weak-phase and other approximations in the analysis of electron microscope images , 1976 .

[29]  N. G. Wrigley,et al.  The lattice spacing of crystalline catalase as an internal standard of length in electron microscopy. , 1968, Journal of ultrastructure research.

[30]  E. Egelman,et al.  Cryo‐electron microscopy and three‐dimensional reconstruction of actin filaments , 1986, Journal of microscopy.

[31]  J. Lepault,et al.  Three-dimensional structure of unstained, frozen-hydrated extended tails of bacteriophage T4. , 1985, Journal of molecular biology.