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Enzyme crystal structure in a neat organic solvent.

ABSTRACT: The crystal structure of the serine protease subtilisin Carlsberg in anhydrous acetonitrile was determined at 2.3 A resolution. It was found to be essentially identical to the three-dimensional structure of the enzyme in water; the differences observed were smaller than those between two independently determined structures in aqueous solution. The hydrogen bond system of the catalytic triad is intact in acetonitrile. The majority (99 of 119) of enzyme-bound, structural water molecules have such a great affinity to subtilisin that they are not displaced even in anhydrous acetonitrile. Of the 12 enzyme-bound acetonitrile molecules, 4 displace water molecules and 8 bind where no water had been observed before. One-third of all subtilisin-bound acetonitrile molecules reside in the active center, occupying the same region (P1, P2, and P3 binding sites) as the specific protein inhibitor eglin c.

SUBMITTER: Fitzpatrick PA

PROVIDER: S-EPMC47416 | biostudies-other | 1993 Sep

REPOSITORIES: biostudies-other

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Enzyme crystal structure in a neat organic solvent.

Fitzpatrick P A PA Steinmetz A C AC Ringe D D Klibanov A M AM

Proceedings of the National Academy of Sciences of the United States of America 19930901 18

The crystal structure of the serine protease subtilisin Carlsberg in anhydrous acetonitrile was determined at 2.3 A resolution. It was found to be essentially identical to the three-dimensional structure of the enzyme in water; the differences observed were smaller than those between two independently determined structures in aqueous solution. The hydrogen bond system of the catalytic triad is intact in acetonitrile. The majority (99 of 119) of enzyme-bound, structural water molecules have such ...[more]

PMID: 8378343

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