PDBsum entry: 2bhy

Hydrolase

PDB id: 2bhy

Contents

Protein chain

580 a.a. *

Ligands

TRS ×2

TRE ×7

BME

GLC ×2

Metals

_MG

Waters ×958

* Residue conservation analysis

PDB id:

2bhy

Name:

Hydrolase

Title:

Crystal structure of deinococcus radiodurans maltooligosyltrehalose trehalohydrolase in complex with trehalose

Structure:

Maltooligosyltrehalose trehalohydrolase. Chain: a. Engineered: yes. Mutation: yes

Source:

Deinococcus radiodurans. Organism_taxid: 243230. Strain: r1. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

1.5Å R-factor: 0.129 R-free: 0.152

Authors:

J.Timmins,H.-K.S.Leiros,G.Leonard,I.Leiros,S.Mcsweeney

Key ref:

J.Timmins et al. (2005). Crystal structure of maltooligosyltrehalose trehalohydrolase from Deinococcus radiodurans in complex with disaccharides. J Mol Biol, 347, 949-963. PubMed id: 15784255 DOI: 10.1016/j.jmb.2005.02.011

Date:

20-Jan-05 Release date: 31-Mar-05

Protein chain

Q9RX51  (TREZ_DEIRA) -  Malto-oligosyltrehalose trehalohydrolase

Seq: 600 a.a.

Struc: 580 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.2.1.141 - 4-alpha-D-((1->4)-alpha-D-glucano)trehalose trehalohydrolase.
• Reaction: Hydrolysis of alpha-(1->4)-D-glucosidic linkage in 4-alpha-D- {(1->4)-alpha-D-glucanosyl}(n) trehalose to yield trehalose and alpha- (1->4)-D-glucan.

 Gene Ontology (GO) functional annotation 

• Cellular component: cytoplasm (1 term)
• Biological process: metabolic process (3 terms)
• Biochemical function: catalytic activity (6 terms)

DOI no: 10.1016/j.jmb.2005.02.011

J Mol Biol 347:949-963 (2005)

PubMed id: 15784255

Crystal structure of maltooligosyltrehalose trehalohydrolase from Deinococcus radiodurans in complex with disaccharides.

J.Timmins, H.K.Leiros, G.Leonard, I.Leiros, S.McSweeney.

ABSTRACT

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.

Selected figure(s)

Figure 2.
Figure 2. Structure of DrMTHase. (a) Topology diagram of DrMTHase. The b-strands are represented as red arrows and a-helices are represented as white cylinders. The b/a repeats of the (b/a)[8] barrel (domain A) are numbered and the inserted subdomains (B, D and E) are indicated by broken lines. (b) and (c) Ribbon representations of the apo form of DrMTHase produced with MOLSCRIPT63and Raster3D.64 Each domain is represented in a different colour and is labelled. The catalytic residues are illustrated in ball-and-stick. The view shown in (c) corresponds to a 60° rotation of the model presented in (b). The disordered loop (residues 473-481) is shown as a broken line, and Aa7 and Ea1 helices are indicated by arrows.

Figure 3.
Figure 3. DrMTHase-trehalose interactions. (a) Ribbon representation of the flexible region of DrMTHase subdomain B interacting with trehalose molecule Tre1. The two conformations of the b-hairpin are displayed in different colours (blue and red), the red one having the highest occupancy. The residues involved in the binding to Tre1 are represented in ball-and-stick. The Figure was prepared with MOLSCRIPT63 and Raster3D.64 (b) A diagram of the maltooligotrehaloside-binding subsites in MTHase. (c) LIGPLOT65 diagram showing the hydrogen bonding network and hydrophobic interactions formed between DrMTHase and the trehalose molecule Tre2 in the +1 and +2 subsites. The amino acid residues of DrMTHase and the glucose moiety (Glc1) that contact Tre2 either directly or via water molecules (represented as blue spheres) are displayed. (d) Diagram of the trehalose molecule Tre2 bound in the substrate-recognition cleft displaying the 2F[o] -F[c] electron density map at 0.7s (blue) and the F[o] -F[c] maps at +4s (green) and -4s (red) for the trehalose Tre2 and the glucose molecule (Glc1). The catalytic residues (D275, E308 and D400) and some of the interacting residues are shown. The Figure was produced with BobScript.66

The above figures are reprinted by permission from Elsevier: J Mol Biol (2005, 347, 949-963) copyright 2005.

Figures were selected by an automated process.