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Nucleation and Crystallization of Globular Proteins: What we Know and What is MissingRecently. much progress has been made in understanding the nucleation and crystallization of globular proteins, including the formation of compositional and structural crystal defects, Insight into the interactions of (screened) protein macro-ions in solution, obtained from light scattering, small angle X-ray scattering and osmotic pressure studies. can guide the search for crystallization conditions. These studies show that the nucleation of globular proteins is governed by the same principles as that of small molecules. However, failure to account for direct and indirect (hydrodynamic) protein interactions in the solutions results in unrealistic aggregation scenarios. Microscopic studies of numerous proteins reveal that crystals grow by the attachment of growth units through the same layer-spreading mechanisms as inorganic crystals. Investigations of the growth kinetics of hen-egg-white lysozyme (HEWL) reveal non-steady behavior under steady external conditions. Long-term variations in growth rates are due to changes in step-originating dislocation groups. Fluctuations on a shorter timescale reflect the non-linear dynamics of layer growth that results from the interplay between interfacial kinetics and bulk transport. Systematic gel electrophoretic analyses suggest that most HEWL crystallization studies have been performed with material containing other proteins at percent levels. Yet, sub-percent levels of protein impurities impede growth step propagation and play a role in the formation of structural/compositional inhomogeneities. In crystal growth from highly purified HEWL solutions, however, such inhomogeneities are much weaker and form only in response to unusually large changes in growth conditions. Equally important for connecting growth conditions to crystal perfection and diffraction resolution are recent advances in structural characterization through high-resolution Bragg reflection profiling and X-ray topography.
Document ID
19990062682
Acquisition Source
Marshall Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Rosenberger, F.
(Alabama Univ. Huntsville, AL United States)
Vekilov, P. G.
(Alabama Univ. Huntsville, AL United States)
Muschol, M.
(Alabama Univ. Huntsville, AL United States)
Thomas, B. R.
(Alabama Univ. Huntsville, AL United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1996
Publication Information
Publication: Journal of Crystal Growth
Publisher: Elsevier Science Publishers
Volume: 168
ISSN: 0022-0248
Subject Category
Solid-State Physics
Funding Number(s)
CONTRACT_GRANT: NSF DMB-91-04630
CONTRACT_GRANT: NAG8-950
CONTRACT_GRANT: NAG8-1161
Distribution Limits
Public
Copyright
Other

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