2bhz
From Proteopedia
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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 , , and as ligands. Active as Alpha-amylase, with EC number 3.2.1.1 Known structural/functional Site: . 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
Page seeded by OCA on Thu Feb 21 16:38:01 2008
