1PBI

CRYSTAL STRUCTURE OF A BOWMAN-BIRK INHIBITOR FROM PEA SEEDS

Summary for 1PBI

• Entry DOI: 10.2210/pdb1pbi/pdb
• Descriptor: BOWMAN-BIRK PROTEINASE INHIBITOR (2 entities in total)
• Functional Keywords: bowman-birk inhibitor, trypsin inhibitor, chymotrypsin inhibitor
• Biological source: Pisum sativum (pea)
• Total number of polymer chains: 2
• Total formula weight: 15860.12

Authors

Li De La Sierra, I.,Brunie, S. (deposition date: 1998-08-20, release date: 1999-01-27, Last modification date: 2024-10-30)

Primary citation

Li de la Sierra, I.,Quillien, L.,Flecker, P.,Gueguen, J.,Brunie, S.
Dimeric crystal structure of a Bowman-Birk protease inhibitor from pea seeds.
J.Mol.Biol., 285:1195-1207, 1999

PubMed Abstract: 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.

PubMed: 9887273
DOI: 10.1006/jmbi.1998.2351

Experimental method

X-RAY DIFFRACTION (2.7 Å)