Crystal and molecular structure of the bovine α-chymotrypsin-eglin c complex at 2.0 Å resolution

Francesco Frigerio, Alessandro Coda, Luisa Pugliese, Claudia Lionetti, Enea Menegatti, Gino Amiconi, Hans Peter Schnebli, Paolo Ascenzi, Martino Bolognesi

Research output: Contribution to journalArticle

Abstract

The crystal structure of the complex between bovine α-chymotrypsin and the leech (Hirudo medicinalis) protein proteinase inhibitor eglin c has been refined at 2.0 Å resolution to a crystallographic R-factor of 0.167. The structure of the complex includes 2290 protein and 143 solvent atoms. Eglin c is bound to the cognate enzyme through interactions involving 11 residues of the inhibitor (sites P5-P4′ in the reactive site loop, P10′ and P23′) and 17 residues from chymotrypsin. Binding of eglin c to the enzyme causes a contained hinge-bending movement around residues P4 and P4′ of the inhibitor. The tertiary structure of chymotrypsin is little affected, with the exception of the 10-13 region, where an ordered structure for the polypeptide chain is observed. The overall binding mode is consistent with those found in other serine proteinase-protein-inhibitor complexes, including those from different inhibition families. Contained, but significant differences are observed in the establishment of intramolecular hydrogen bonds and polar interactions stabilizing the structure of the intact inhibitor, if the structure of eglin c in its complex with chymotrypsin is compared with that of other eglin c-serine proteinase complexes.

Original languageEnglish
Pages (from-to)107-123
Number of pages17
JournalJournal of Molecular Biology
Volume225
Issue number1
DOIs
Publication statusPublished - May 5 1992

Keywords

  • bovine α-chymotrypsin
  • eglin c
  • protein structures
  • proteinase protein inhibitors
  • serine proteinases

ASJC Scopus subject areas

  • Virology

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    Frigerio, F., Coda, A., Pugliese, L., Lionetti, C., Menegatti, E., Amiconi, G., Schnebli, H. P., Ascenzi, P., & Bolognesi, M. (1992). Crystal and molecular structure of the bovine α-chymotrypsin-eglin c complex at 2.0 Å resolution. Journal of Molecular Biology, 225(1), 107-123. https://doi.org/10.1016/0022-2836(92)91029-O