ISSN:
1399-0047
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
X-ray diffuse scattering from protein crystals is, at the moment, the only available experimental process to be directly sensitive to long-range correlations between protein-atom displacements. It is shown here that calculations based on independent rigid-body displacements of individual molecules yield a description in good agreement with the experimental diffuse-scattering pattern displayed by tetragonal crystals of hen egg-white lysozyme (HEWL) In particular, it appears that molecular rigid-body translations and rigid- body rotations appear roughly in the same proportion as the average atomic mean-square positional fluctuations. The crystallographic temperature-factor analysis by TLS (translation/libration/screw) refinement, performed by Sternberg, Grace & Phillips [Sternberg, Grace, & Phillips (1979). J. Mol. Biol. 130, 231–253], is then confirmed and completed by a quantitative estimation of the molecular rigid-body translation contributions. The major contribution of molecular rigid- body displacements to the average atomic mean-square positional fluctuations, contradicts a previous analysis of the tetragonal HEWL diffuse-scattering data by Clarage, Clarage, Phillips, Sweet & Caspar [Clarage, Clarage, Phillips, Sweet & Caspar (1992). Proteins Struct. Funct. Genet. 12, 145–157] which concluded that short-range correlations dominate. The origin of these opposite conclusions mostly lies in the different hypotheses made to model diffuse scattering, underlying the limits of the `homogeneous disorder' model.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0907444996002594
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