1bip
From Proteopedia
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BIFUNCTIONAL PROTEINASE INHIBITOR TRYPSIN/A-AMYLASE FROM SEEDS OF RAGI (ELEUSINE CORACANA GAERTNERI)
Overview
The three-dimensional structure of the bifunctional alpha-amylase/trypsin, inhibitor (RBI) from seeds of ragi (Eleusine coracana Gaertneri) has been, determined in solution using multidimensional 1H and 15N NMR spectroscopy., The inhibitor consists of 122 amino acids, with 5 disulfide bridges, and, belongs to the plant alpha-amylase/trypsin inhibitor family for which no, three-dimensional structures have yet been available. The structure of the, inhibitor was determined on the basis of 1131 interresidue interproton, distance constraints derived from nuclear Overhauser enhancement, measurements and 52 phi angles, supplemented by 9 psi and 51 chi 1 angles., RBI consists of a globular four-helix motif with a simple "up-and-down", topology. The helices are between residues 18-29, 37-51, 58-65, and 87-94., A fragment from Val 67 to Ser 69 and Gln 73 to Glu 75 forms an, antiparallel beta-sheet. The fold of RBI represents a new motif among the, serine proteinase inhibitors. The trypsin binding loop of RBI adopts the, "canonical", substrate-like conformation which is highly conserved among, serine proteinase inhibitors. The binding loop is stabilized by the two, adjacent alpha-helices 1 and 2. This motif is also novel and not found in, known structures of serine proteinase inhibitors. The three-dimensional, structure of RBI together with biochemical data suggests the location of, the alpha-amylase binding site on the face of the molecule opposite to the, site of the trypsin binding loop. The RBI fold should be general for all, members of the RBI family because conserved residues among the members of, the family from the core of the structure.
About this Structure
1BIP is a Single protein structure of sequence from Eleusine coracana. Full crystallographic information is available from OCA.
Reference
Determination of the three-dimensional structure of the bifunctional alpha-amylase/trypsin inhibitor from ragi seeds by NMR spectroscopy., Strobl S, Muhlhahn P, Bernstein R, Wiltscheck R, Maskos K, Wunderlich M, Huber R, Glockshuber R, Holak TA, Biochemistry. 1995 Jul 4;34(26):8281-93. PMID:7599120
Page seeded by OCA on Tue Nov 20 11:40:59 2007
