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Countering Solutal Buoyant Convection with High Magnetic FieldsAn important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemist, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitant, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in microgravity, we have been able to dramatically effect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. We postulate that limited convection in a magnetic field will provide the environment for the growth of high quality crystals. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately positioning the crystal growth cell so that the magnetic susceptibility force counteracts terrestrial gravity. The general objective is to test the hypothesis of convective control using a strong magnetic field and magnetic field gradient and to understand the nature of the various forces that come into play. Specifically we aim to delineate causative factors and to quantify them through experiments, analysis and numerical modeling. The paper will report on the current status of the investigation and discuss results from the experimental and modeling efforts.
Document ID
20030064083
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Ramachandran, N.
(Universities Space Research Association Huntsville, AL, United States)
Leslie, F. W.
(Universities Space Research Association Huntsville, AL, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2002
Subject Category
Inorganic, Organic And Physical Chemistry
Meeting Information
Meeting: 41st Aerospace Sciences Meeting and Exhibit
Location: Reno, NV
Country: United States
Start Date: January 6, 2003
End Date: January 9, 2003
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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