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Locating interaction sites on proteins: The crystal structure of thermolysin soaked in 2% to 100% isopropanol
Author(s) -
English Andrew C.,
Done Sarah H.,
Caves Leo S.D.,
Groom Colin R.,
Hubbard Roderick E.
Publication year - 1999
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/(sici)1097-0134(19991201)37:4<628::aid-prot13>3.0.co;2-g
Subject(s) - thermolysin , solvent , chemistry , crystal structure , crystallography , interaction energy , protein crystallization , crystal (programming language) , crystallization , molecule , organic chemistry , enzyme , trypsin , programming language , computer science
Multiple‐solvent crystal structure determination (MSCS) allows the position and orientation of bound solvent fragments to be identified by determining the structure of protein crystals soaked in organic solvents. We have extended this technique by the determination of high‐resolution crystal structures of thermolysin (TLN), generated from crystals soaked in 2% to 100% isopropanol. The procedure causes only minor changes to the conformation of the protein, and an increasing number of isopropanol interaction sites could be identified as the solvent concentration is increased. Isopropanol occupies all four of the main subsites in the active site, although this was only observed at very high concentrations of isopropanol for three of the four subsites. Analysis of the isopropanol positions shows little correlation with interaction energy computed using a molecular mechanics force field, but the experimentally determined positions of isopropanol are consistent with the structures of known protein‐ligand complexes of TLN. Proteins 1999;37:628–640. ©1999 Wiley‐Liss, Inc.