PDBsum entry 1mvz

Hydrolase inhibitor

PDB id: 1mvz

Contents

Protein chain

62 a.a. *

* Residue conservation analysis

PDB id:

1mvz

Name:

Hydrolase inhibitor

Title:

Nmr solution structure of a bowman birk inhibitor isolated from snail medic seeds (medicago scutellata)

Structure:

Bowman-birk type protease inhibitor, (msti). Chain: a. Synonym: msti

Source:

Medicago scutellata. Organism_taxid: 36901. Tissue: seeds

NMR struc:

15 models

Authors:

M.Catalano,L.Ragona,H.Molinari,A.Tava,L.Zetta

Key ref:

M.Catalano et al. (2003). Anticarcinogenic Bowman Birk inhibitor isolated from snail medic seeds (Medicago scutellata): solution structure and analysis of self-association behavior. Biochemistry, 42, 2836-2846. PubMed id: 12627949 DOI: 10.1021/bi020576w

Date:

27-Sep-02 Release date: 22-Apr-03

Protein chain

P80321  (IBB_MEDSC) -  Bowman-Birk type proteinase inhibitor from Medicago scutellata

Seq: 62 a.a.

Struc: 62 a.a.

DOI no: 10.1021/bi020576w

Biochemistry 42:2836-2846 (2003)

PubMed id: 12627949

Anticarcinogenic Bowman Birk inhibitor isolated from snail medic seeds (Medicago scutellata): solution structure and analysis of self-association behavior.

M.Catalano, L.Ragona, H.Molinari, A.Tava, L.Zetta.

ABSTRACT

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.