X-ray crystal structure of cross-linked subtilisin Carlsberg in water vs. Acetonitrile

Abstract

The crystal structure of subtilisin Carlsberg lightly cross-linked with glutaraldehyde was solved in aqueous solution by X-ray crystallography at 2.3 AÅ resolution. It was found to be virtually identical to the recently determined (Fitzpatrick, P.A., Steinmetz, A.C.U., Ringe, D.A. and Klibanov, A.M. (1993) Proc. Natl. Acad. Sci. USA 90, 8653) structure of the cross-linked enzyme in anhydrous acetonitrile. The latter structure was found to be significantly more rigid than in water, as reflected by their average B factors. The numbers of subtilisin-bound water molecules in the two structures are similar (114 and 99 in water and in acetonitrile, respectively) but the locations of some half of these bound waters are distinct. © 1994 Academic Press, Inc.