1c2a
From Proteopedia
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CRYSTAL STRUCTURE OF BARLEY BBI
Overview
The Bowman-Birk trypsin inhibitor from barley seeds (BBBI) consists of 125, amino acid residues with two inhibitory loops. Its crystal structure in, the free state has been determined by the multiwavelength anomalous, diffraction (MAD) method and has been refined to a crystallographic, R-value of 19.1 % for 8.0-1.9 A data. This is the first report on the, structure of a 16 kDa double-headed Bowman-Birk inhibitor (BBI) from, monocotyledonous plants and provides the highest resolution picture of a, BBI to date. The BBBI structure consists of 11 beta-strands and the loops, connecting these beta-strands but it lacks alpha-helices. BBBI folds into, two compact domains of similar tertiary structure. Each domain shares the, same overall fold with 8 kDa dicotyledonous BBIs. The five disulfide, bridges in each domain are a subset of the seven disulfide bridges in 8, kDa dicotyledonous BBIs. Two buried water molecules form hydrogen bonds to, backbone atoms in the core of each domain. One interesting feature of this, two-domain inhibitor structure is that the two P1 residues (Arg17 and, Arg76) are approximately 40 A apart, allowing the two reactive-site loops, to bind to and to inhibit two trypsin molecules simultaneously and, independently. The conformations of the reactive-site loops of BBBI are, highly similar to those of other substrate-like inhibitors. This structure, provides the framework for modeling of the 1:2 complex between BBBI and, trypsin.
About this Structure
1C2A is a Single protein structure of sequence from Hordeum vulgare. Full crystallographic information is available from OCA.
Reference
Crystal structure of a 16 kDa double-headed Bowman-Birk trypsin inhibitor from barley seeds at 1.9 A resolution., Song HK, Kim YS, Yang JK, Moon J, Lee JY, Suh SW, J Mol Biol. 1999 Nov 12;293(5):1133-44. PMID:10547291
Page seeded by OCA on Tue Nov 20 12:06:05 2007
