1bgp

From Proteopedia

---

Revision as of 22:02, 24 November 2007

proteopedia linkproteopedia link

spinqualitylabelsall models 1bgp, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTAL STRUCTURE OF BARLEY GRAIN PEROXIDASE 1

Overview

The crystal structure of the major peroxidase of barley grain (BP 1) has, been solved by molecular replacement and phase combination and refined to, an R-factor of 19.2% for all data between 38 and 1.9 A. The refined model, includes amino acid residues 1-309, one calcium ion, one sodium ion, iron-protoporphyrin IX, and 146 solvent molecules. BP 1 has the apparently, unique property of being unable to catalyze the reaction with the primary, substrate hydrogen peroxide to form compound I at pH values > 5, a feature, investigated by obtaining crystal structure data at pH 5.5, 7.5, and 8.5., Structural comparison shows that the overall fold of inactive barley grain, peroxidase at these pH values resembles that of both horseradish, peroxidase C and peanut peroxidase. The key differences between the, structures of active horseradish peroxidase C and inactive BP 1 include, the orientation of the catalytic distal histidine, disruption of a, hydrogen bond between this histidine and a conserved asparagine, and, apparent substitution of calcium at the distal cation binding site with, sodium at pH 7.5. These profound changes are a result of a dramatic, structural rearrangement to the loop region between helices B and C. This, is the first time that structural rearrangements linked to active site, chemistry have been observed by crystallography in the peroxidase domain, distal to heme.

About this Structure

1BGP is a Single protein structure of sequence from Hordeum vulgare with CA, NA and HEM as ligands. Active as Peroxidase, with EC number 1.11.1.7 Full crystallographic information is available from OCA.

Reference

Structure of barley grain peroxidase refined at 1.9-A resolution. A plant peroxidase reversibly inactivated at neutral pH., Henriksen A, Welinder KG, Gajhede M, J Biol Chem. 1998 Jan 23;273(4):2241-8. PMID:9442067

Page seeded by OCA on Sun Nov 25 00:10:26 2007