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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 4 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 h 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
20000110582
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to 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)
Rose, M. Franklin
Date Acquired
August 19, 2013
Publication Date
January 1, 2000
Subject Category
Life Sciences (General)
Meeting Information
Meeting: Crystallization of Biological Macromolecules
Location: Sandestin, FL
Country: United States
Start Date: May 1, 2000
Funding Number(s)
CONTRACT_GRANT: NCC8-66
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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