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Title: Thermal contraction of aqueous glycerol and ethylene glycol solutions for optimized protein-crystal cryoprotection
The thermal contraction of aqueous cryoprotectant solutions on cooling to cryogenic temperatures is of practical importance in protein cryocrystallography and in biological cryopreservation. In the former case, differential contraction on cooling of protein molecules and their lattice relative to that of the internal and surrounding solvent may lead to crystal damage and the degradation of crystal diffraction properties. Here, the amorphous phase densities of aqueous solutions of glycerol and ethylene glycol at T = 77 K have been determined. Densities with accuracies of <0.5% to concentrations as low as 30%( w / v ) were determined by rapidly cooling drops with volumes as small as 70 pl, assessing their optical clarity and measuring their buoyancy in liquid nitrogen–argon solutions. The use of these densities in contraction matching of internal solvent to the available solvent spaces is complicated by several factors, most notably the exclusion of cryoprotectants from protein hydration shells and the expected deviation of the contraction behavior of hydration water from bulk water. The present methods and results will assist in developing rational approaches to cryoprotection and an understanding of solvent behavior in protein crystals.  more » « less
Award ID(s):
1330685
NSF-PAR ID:
10019226
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
Acta Crystallographica Section D Structural Biology
Volume:
72
Issue:
6
ISSN:
2059-7983
Page Range / eLocation ID:
742 to 752
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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