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1hd9
From Proteopedia
THE BOWMAN-BIRK INHIBITOR REACTIVE SITE LOOP SEQUENCE REPRESENTS AN INDEPENDENT STRUCTURAL BETA-HAIRPIN MOTIF
Overview
We have determined the NMR structure in aqueous solution of a disulphide-cyclised 11-residue peptide that forms a stable beta-hairpin, incorporating a type VIb beta-turn. The structure is found to be extremely well ordered for a short peptide, with the 30 lowest energy simulated annealing structures having an average pairwise r.m.s. deviation of only 0.36 A over the backbone. All but three side-chains adopt distinct conformations, allowing a detailed analysis of their involvement in cross-strand interactions. The peptide sequence analysed originates from a previously reported study, which identified potent inhibitors of human leukocyte elastase from screening a combinatorial peptide library based on the short protein beta-sheet segment that forms the reactive site loop of Bowman-Birk inhibitors. A detailed comparison of the peptide's solution structure with the corresponding region in the whole protein structure reveals a very good correspondence not only for the backbone (r.m.s. deviation approximately 0.7 A) but also for the side-chains. This isolated beta-hairpin retains the biologically active "canonical conformation" typical of small serine proteinase inhibitor proteins, which explains why it retains inhibitory activity. Since the structural integrity is sequence-inherent and does not depend upon the presence of the remaining protein, this beta-hairpin represents an independent structural motif and so provides a useful model of this type of protein architecture and its relation to biological function. The relationship between the conformation of this beta-hairpin and its biological activity is discussed.
About this Structure
1HD9 is a Single protein structure. Full crystallographic information is available from OCA.
Reference
The Bowman-Birk inhibitor reactive site loop sequence represents an independent structural beta-hairpin motif., Brauer AB, Kelly G, McBride JD, Cooke RM, Matthews SJ, Leatherbarrow RJ, J Mol Biol. 2001 Mar 2;306(4):799-807. PMID:11243789 Page seeded by OCA on Fri May 2 18:43:28 2008
