Biomolecular dynamics: A report from a workshop in Gysinge, Sweden, October 4–7, 1982

1984 ◽  
Vol 17 (2) ◽  
pp. 125-151 ◽  
Author(s):  
Olle Edholm ◽  
Lennart Nilsson ◽  
Otto Berg ◽  
Måns Ehrenberg ◽  
Flora Claesens ◽  
...  

From the results of X-ray crystallography a wealth of information is now available concerning the detailed molecular structure of proteins, nucleic acids, and membrane components. This has made it possible to apply successfully various spectroscopie techniques for time resolved studies as well as theoretical simulations of internal molecular dynamics in the biological macromolecules and molecular aggregates. We were particularly pleased to see professor Ivar Waller among the participants of the workshop since new use of the wellknown Debye–Waller factor has greatly contributed to this development. A molecular picture is presently emerging including the dimension of time which ultimately will give us a detailed understanding of the functional interactions between biomolecules in general, and in particular enzyme catalysis, nucleic acid functions, and transport of matter and information through membranes.

Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).


1988 ◽  
Vol 21 (4) ◽  
pp. 429-477 ◽  
Author(s):  
W. Kühlbrandt

As recently as 10 years ago, the prospect of solving the structure of any membrane protein by X-ray crystallography seemed remote. Since then, the threedimensional (3-D) structures of two membrane protein complexes, the bacterial photosynthetic reaction centres of Rhodopseudomonas viridis (Deisenhofer et al. 1984, 1985) and of Rhodobacter sphaeroides (Allen et al. 1986, 1987 a, 6; Chang et al. 1986) have been determined at high resolution. This astonishing progress would not have been possible without the pioneering work of Michel and Garavito who first succeeded in growing 3-D crystals of the membrane proteins bacteriorhodopsin (Michel & Oesterhelt, 1980) and matrix porin (Garavito & Rosenbusch, 1980). X-ray crystallography is still the only routine method for determining the 3-D structures of biological macromolecules at high resolution and well-ordered 3-D crystals of sufficient size are the essential prerequisite.


1989 ◽  
Vol 72 (11) ◽  
pp. 1135-1140 ◽  
Author(s):  
R.C. Shukla ◽  
H. Hübschle

1982 ◽  
Vol 45 (2) ◽  
pp. 287-298 ◽  
Author(s):  
N. Garcia ◽  
A. A. Maradudin ◽  
V. Celli

IUCrJ ◽  
2016 ◽  
Vol 3 (4) ◽  
pp. 247-258 ◽  
Author(s):  
Tsunetomo Yamada ◽  
Hiroyuki Takakura ◽  
Holger Euchner ◽  
Cesar Pay Gómez ◽  
Alexei Bosak ◽  
...  

The detailed atomic structure of the binary icosahedral (i) ScZn7.33quasicrystal has been investigated by means of high-resolution synchrotron single-crystal X-ray diffraction and absolute scale measurements of diffuse scattering. The average atomic structure has been solved using the measured Bragg intensity data based on a six-dimensional model that is isostructural to the i-YbCd5.7one. The structure is described with a quasiperiodic packing of large Tsai-type rhombic triacontahedron clusters and double Friauf polyhedra (DFP), both resulting from a close-packing of a large (Sc) and a small (Zn) atom. The difference in chemical composition between i-ScZn7.33and i-YbCd5.7was found to lie in the icosahedron shell and the DFP where in i-ScZn7.33chemical disorder occurs on the large atom sites, which induces a significant distortion to the structure units. The intensity in reciprocal space displays a substantial amount of diffuse scattering with anisotropic distribution, located around the strong Bragg peaks, that can be fully interpreted as resulting from phason fluctuations, with a ratio of the phason elastic constantsK2/K1= −0.53,i.e.close to a threefold instability limit. This induces a relatively large perpendicular (or phason) Debye–Waller factor, which explains the vanishing of `high-Qperp' reflections.


1997 ◽  
Vol 30 (5) ◽  
pp. 555-556 ◽  
Author(s):  
G. Kurisu ◽  
A. Sugimoto ◽  
Y. Kai ◽  
S. Harada

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