1gl1

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spinqualitylabelsall models 1gl1, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

STRUCTURE OF THE COMPLEX BETWEEN BOVINE ALPHA-CHYMOTRYPSIN AND PMP-C, AN INHIBITOR FROM THE INSECT LOCUSTA MIGRATORIA

Overview

The crystal structures of two homologous inhibitors (PMP-C and PMP-D2v), from the insect Locusta migratoria have been determined in complex with, bovine alpha-chymotrypsin at 2.1- and 3.0-A resolution, respectively., PMP-C is a potent bovine alpha-chymotrypsin inhibitor whereas native, PMP-D2 is a weak inhibitor of bovine trypsin. One unique mutation at the, P1 position converts PMP-D2 into a potent bovine alpha-chymotrypsin, inhibitor. The two peptides have a similar overall conformation, which, consists of a triple-stranded antiparallel beta-sheet connected by three, disulfide bridges, thus defining a novel family of serine protease, inhibitors. They have in common the protease interaction site, which is, composed of the classical protease binding loop (position P5 to P'4, corresponding to residues 26-34) and of an internal segment (residues, 15-18), held together by two disulfide bridges. Structural divergences, between the two inhibitors result in an additional interaction site, between PMP-D2v (position P10 to P6, residues 21-25) and the residues, 172-175 of alpha-chymotrypsin. This unusual interaction may be responsible, for species selectivity. A careful comparison of data on bound and free, inhibitors (from this study and previous NMR studies, respectively), suggests that complexation to the protease stabilizes the flexible binding, loop (from P5 to P'4).

About this Structure

1GL1 is a Protein complex structure of sequences from Bos taurus with CD as ligand. Active as Chymotrypsin, with EC number 3.4.21.1 Full crystallographic information is available from OCA.

Reference

Complexation of two proteic insect inhibitors to the active site of chymotrypsin suggests decoupled roles for binding and selectivity., Roussel A, Mathieu M, Dobbs A, Luu B, Cambillau C, Kellenberger C, J Biol Chem. 2001 Oct 19;276(42):38893-8. Epub 2001 Aug 8. PMID:11495915

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