1pbi
From Proteopedia
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CRYSTAL STRUCTURE OF A BOWMAN-BIRK INHIBITOR FROM PEA SEEDS
Overview
The trypsin/chymotrypsin inhibitors from winter pea seeds (PsTI) are, members of the Bowman-Birk protease inhibitor (BBPI) family. The crystal, structure of the isoform PsTI-IVb was determined by molecular replacement, at 2.7 A resolution using the X-ray co-ordinates of the soybean inhibitor, as a search model. The inhibitor crystallized with a nearly perfect 2-fold, symmetric dimer in the asymmetric unit. Although the overall structure is, very similar to that seen in other BBPIs, there are notable new structural, features. Unlike the previously reported X-ray structures of BBPIs, the, structure of PsTI-IVb includes the C-terminal segment of the molecule. The, C-terminal tail of each subunit is partly beta-stranded and interacts with, the 2-fold symmetry-related subunit, forming a beta-sheet with strands A, and B of this subunit. The dimer is mainly stabilized by a large internal, hydrogen-bonded network surrounded by two hydrophobic links. Fluorescence, anisotropy decay measurements show that residues Tyr59 and Tyr43 are, mobile in the picosecond time scale with a large amplitude. The, fluorescence study and a molecular model of the simultaneous binding of, PsTI-IVb to porcine trypsin and bovine chymotrypsin are compatible only, with a monomeric state of the functional molecule in solution.
About this Structure
1PBI is a Single protein structure of sequence from Pisum sativum. Full crystallographic information is available from OCA.
Reference
Dimeric crystal structure of a Bowman-Birk protease inhibitor from pea seeds., Li de la Sierra I, Quillien L, Flecker P, Gueguen J, Brunie S, J Mol Biol. 1999 Jan 22;285(3):1195-207. PMID:9887273
Page seeded by OCA on Tue Nov 20 23:39:58 2007
