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Hyperquenching for protein cryocrystallography
Author(s) -
Warkentin Matthew,
Berejnov Viatcheslav,
Husseini Naji S.,
Thorne Robert E.
Publication year - 2006
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889806037484
Subject(s) - crystallization , cryoprotectant , liquid nitrogen , protein crystallization , tray , nitrogen , aqueous solution , propane , glycerol , materials science , drop (telecommunication) , slow cooling , chemistry , analytical chemistry (journal) , chromatography , composite material , organic chemistry , mechanical engineering , embryo , telecommunications , engineering , computer science , cryopreservation , biology , microbiology and biotechnology
When samples having volumes characteristic of protein crystals are plunge cooled in liquid nitrogen or propane, most cooling occurs in the cold gas layer above the liquid. By removing this cold gas layer, cooling rates for small samples and modest plunge velocities are increased to 1.5 × 10 4 K s −1 , with increases of a factor of 100 over current best practice possible with 10 µm samples. Glycerol concentrations required to eliminate water crystallization in protein‐free aqueous mixtures drop from ∼28% w / v to as low as 6% w / v . These results will allow many crystals to go from crystallization tray to liquid cryogen to X‐ray beam without cryoprotectants. By reducing or eliminating the need for cryoprotectants in growth solutions, they may also simplify the search for crystallization conditions and for optimal screens. The results presented here resolve many puzzles, such as why plunge cooling in liquid nitrogen or propane has, until now, not yielded significantly better diffraction quality than gas‐stream cooling.