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Magnetic Control of Convection during Protein CrystallizationAn 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 bio-chemists, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitants, other possible phases of the protein, foreign particles, the walls of 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 affect the movement and distribution of macromolecules in the fluid, and thus their transport, f o d o n 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 counteracts on for this purpose and the convective damping is realized by appropriately positioning the crystal growth cell so that the magnetic susceptibility force counteract terrestrial gravity. The genera1 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 experimental results using paramagentic salts and solutions in magnetic fields and compare them to analyticalpr~ctions.
Document ID
20040111419
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Ramachandran, N.
(BAE Systems Analytical Solutions, Inc. Huntsville, AL, United States)
Leslie, F. W.
(BAE Systems Analytical Solutions, Inc. Huntsville, AL, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2004
Subject Category
Life Sciences (General)
Meeting Information
Meeting: International Conference on Crystal Growth
Location: Grenoble
Country: France
Start Date: August 9, 2004
End Date: August 13, 2004
Funding Number(s)
CONTRACT_GRANT: NAS8-02096
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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