2bhz

From Proteopedia

Revision as of 15:33, 5 November 2007

CRYSTAL STRUCTURE OF DEINOCOCCUS RADIODURANS MALTOOLIGOSYLTREHALOSE TREHALOHYDROLASE IN COMPLEX WITH MALTOSE

Overview

Trehalose (alpha-D-glucopyranosyl-1,1-alpha-D-glucopyranose) is a, non-reducing diglucoside found in various organisms that serves as a, carbohydrate reserve and as an agent that protects against a variety of, physical and chemical stresses. Deinococcus radiodurans possesses an, alternative biosynthesis pathway for the synthesis of trehalose from, maltooligosaccharides. This reaction is mediated by two enzymes:, maltooligosyltrehalose synthase (MTSase) and maltooligosyltrehalose, trehalohydrolase (MTHase). Here, we present the 1.1A resolution crystal, structure of MTHase. It consists of three major domains: two beta-sheet, domains and a conserved glycosidase (beta/alpha)8 barrel catalytic domain., Three subdomains consisting of short insertions were identified within the, catalytic domain. Subsequently, structures of MTHase in complex with, maltose and trehalose were obtained at 1.2 A and 1.5 A resolution, respectively. These structures reveal the importance of the three inserted, subdomains in providing the key residues required for substrate, recognition. Trehalose is recognised specifically in the +1 and +2 binding, subsites by an extensive hydrogen-bonding network and a strong hydrophobic, stacking interaction in between two aromatic residues. Moreover, upon, binding to maltose, which mimics the substrate sugar chain, a major, concerted conformational change traps the sugar chain in the active site., The presence of magnesium in the active site of the MTHase-maltose complex, suggests that MTHase activity may be regulated by divalent cations.

About this Structure

2BHZ is a Single protein structure of sequence from Deinococcus radiodurans with MAL, MG, BME and TRS as ligands. Active as Alpha-amylase, with EC number 3.2.1.1 Structure known Active Site: AC1. Full crystallographic information is available from OCA.

Reference

Crystal structure of maltooligosyltrehalose trehalohydrolase from Deinococcus radiodurans in complex with disaccharides., Timmins J, Leiros HK, Leonard G, Leiros I, McSweeney S, J Mol Biol. 2005 Apr 15;347(5):949-63. PMID:15784255

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