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X‐ray crystal structures of a severely desiccated protein
Author(s) -
Bell Jeffrey A.
Publication year - 1999
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.8.10.2033
Subject(s) - crystallography , intermolecular force , crystal structure , chemistry , protein crystallization , crystal (programming language) , chemical physics , protein structure , bovine pancreatic ribonuclease , ribonuclease , molecule , crystallization , biochemistry , programming language , organic chemistry , computer science , rna , gene
Unlike most protein crystals, form IX of bovine pancreatic ribonuclease A diffracts well when severely dehydrated. Crystal structures have been solved after 2.5 and 4 days of desiccation with CaSO 4 , at 1.9 and 2.0 Å resolution, respectively. The two desiccated structures are very similar. An RMS displacement of 1.6 Å is observed for main‐chain atoms in each structure when compared to the hydrated crystal structure with some large rearrangements observed in loop regions. The structural changes are the result of intermolecular contacts formed by strong electrostatic interactions in the absence of a high dielectric medium. The electron density is very diffuse for some surface loops, consistent with a very disordered structure. This disorder is related to the conformational changes. These results help explain conformational changes during the lyophilization of protein and the associated phenomena of denaturation and molecular memory.