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The Effect of Solution Thermal History on Chicken Egg White Lysozyme NucleationProteins are highly flexible molecules and often exhibit defined conformational changes in response to changes in the ambient temperature. Chicken egg white lysozyme has been previously shown to undergo an apparent structural change when warmed above the tetragonal/orthorhombic phase transition temperature. This is reflected by a change in the habit of the tetragonal and orthorhombic crystals so formed. In this study, we show that possible conformational changes induced by heating are stable and apparently non-reversible by simple cooling. Exposure of protein solutions to temperatures above the phase change transition temperature, before combining with precipitant solution to begin crystallization, reduces final crystal numbers. Protein that is briefly warmed to 37 C, then cooled shows no sign of reversal to the unheated nucleation behavior even after storage for four weeks at 4 C. The change in nucleation behavior of tetragonal lysozyme crystals, attributed to a structural shift, occurs faster the greater the exposure to temperature above the equi-solubility point for the two phases. Heating for 2 hours at 48 C reduces crystal numbers by 20 fold in comparison to the same solution heated for the same time at 30 C. Thermal treatment of solutions is therefore a possible tool to reduce crystal numbers and increase crystal size. The effects of a protein's previous thermal history are now shown to be a potentially critical factor in subsequent macromolecule crystal nucleation and growth studies.
Document ID
20020020662
Acquisition Source
Marshall Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Burke, Michael W.
(Alabama Univ. Huntsville, AL United States)
Judge, Russell A.
(Alabama Univ. Huntsville, AL United States)
Pusey, Marc L.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Date Acquired
August 20, 2013
Publication Date
January 1, 2001
Publication Information
Publication: Journal of Crystal Growth
Publisher: Elsevier Science B.V.
Volume: 232
ISSN: 0022-0248
Subject Category
Life Sciences (General)
Funding Number(s)
PROJECT: RTOP 101-11-32
Distribution Limits
Public
Copyright
Other

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