1mvz

From Proteopedia

NMR solution structure of a Bowman Birk inhibitor isolated from snail medic seeds (Medicago Scutellata)

Overview

The high-resolution three-dimensional structure of a Bowman Birk, inhibitor, purified from snail medic seeds (Medicago scutellata) (MSTI), has been determined in solution by 1H NMR spectroscopy at pH 5.6 and 27, degrees C. The structure of MSTI comprises two distinct symmetric domains, each composed of a three-stranded beta-sheet containing a VIb type loop, where the active sites are located. A characteristic geometry of three, aromatic residues confers stability to this protein, and we observe that, this feature is conserved in all the Bowman Birk inhibitors of known, structure. The two active domains exhibit different conformational, features: the second domain displays higher flexibility and hydrophobicity, with respect to the first one, and these properties have been correlated, to a lower trypsin inhibitory specificity, in agreement with titration, studies that have shown a stoichiometric ratio MSTI:trypsin of 1:1.5. NMR, analysis indicated that MSTI undergoes self-association at concentrations, higher than 2 mM, and the residues involved in this mechanism are, localized at opposite faces of the molecule, having the highest positive, and negative potential, respectively, thus indicating that electrostatic, intermolecular interactions are the driving forces for MSTI association., Most of the residues affected by self-association are highly conserved in, BBIs from different seeds, suggesting a functional relevance for these, charged superficial patches, possibly involved in the interaction with, other enzymes or macromolecules, thus triggering anti-carcinogenic, activity.

About this Structure

1MVZ is a Single protein structure of sequence from Medicago scutellata. Full crystallographic information is available from OCA.

Reference

Anticarcinogenic Bowman Birk inhibitor isolated from snail medic seeds (Medicago scutellata): solution structure and analysis of self-association behavior., Catalano M, Ragona L, Molinari H, Tava A, Zetta L, Biochemistry. 2003 Mar 18;42(10):2836-46. PMID:12627949

Page seeded by OCA on Tue Nov 20 21:44:50 2007