PDBsum entry: 1gz5

Synthase

PDB id: 1gz5

Contents

Protein chains

456 a.a. *

Ligands

UDP ×4

G6P ×4

IMD ×4

Waters ×288

* Residue conservation analysis

PDB id:

1gz5

Name:

Synthase

Title:

Trehalose-6-phosphate synthase. Otsa

Structure:

Alpha-trehalose-phosphate synthase. Chain: a, b, c, d. Synonym: trehalose-6-phosphate synthase, udp-forming udp-glucose-glucosephosphate, glucosyltransferase. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 316407. Strain: w3110. Expressed in: escherichia coli. Expression_system_taxid: 511693. Expression_system_variant: b834. Other_details: c-terminal his-tag fusion

Biol. unit:

Monomer (from PDB file)

Resolution:

2.43Å R-factor: 0.207 R-free: 0.228

Authors:

R.P.Gibson,J.P.Turkenburg,G.J.Davies

Key ref:

R.P.Gibson et al. (2002). Insights into trehalose synthesis provided by the structure of the retaining glucosyltransferase OtsA. Chem Biol, 9, 1337-1346. PubMed id: 12498887 DOI: 10.1016/S1074-5521(02)00292-2

Date:

15-May-02 Release date: 07-Feb-03

Protein chains

P31677  (OTSA_ECOLI) -  Alpha,alpha-trehalose-phosphate synthase [UDP-forming]

Seq: 474 a.a.

Struc: 456 a.a.

Enzyme reactions

• Enzyme class: E.C.2.4.1.15 - Alpha,alpha-trehalose-phosphate synthase (UDP-forming).
• Reaction: UDP-glucose + D-glucose 6-phosphate = UDP + alpha,alpha-trehalose 6-phosphate

UDP-glucose + D-glucose 6-phosphate (Bound ligand (Het Group name = G6P) corresponds exactly) = UDP (Bound ligand (Het Group name = UDP) corresponds exactly) + alpha,alpha-trehalose 6-phosphate

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

 Gene Ontology (GO) functional annotation 

• Biological process: response to stress (2 terms)
• Biochemical function: catalytic activity (4 terms)

reference

DOI no: 10.1016/S1074-5521(02)00292-2

Chem Biol 9:1337-1346 (2002)

PubMed id: 12498887

Insights into trehalose synthesis provided by the structure of the retaining glucosyltransferase OtsA.

R.P.Gibson, J.P.Turkenburg, S.J.Charnock, R.Lloyd, G.J.Davies.

ABSTRACT

Trehalose is a nonreducing disaccharide that plays a major role in many organisms, most notably in survival and stress responses. In Mycobacterium tuberculosis, it plays a central role as the carbohydrate core of numerous immunogenic glycolipids including "cord factor" (trehalose 6,6'-dimycolate). The classical pathway for trehalose synthesis involves the condensation of UDP-glucose and glucose-6-phosphate to afford trehalose-6-phosphate, catalyzed by the retaining glycosyltransferase OtsA. The configurations of two anomeric positions are set simultaneously, resulting in the formation of a double glycoside. The three-dimensional structure of the Escherichia coli OtsA, in complex with both UDP and glucose-6-phosphate, reveals the active site at the interface of two beta/alpha/beta domains. The overall structure and the intimate details of the catalytic machinery reveal a striking similarity to glycogen phosphorylase, indicating a strong evolutionary link and suggesting a common catalytic mechanism.

Selected figure(s)

Figure 1.
Figure 1. Glycosyltransfer with Inversion and Retention(A) The synthesis of glycosidic bonds from activated nucleotide-sugar donors may proceed with either inversion or retention of anomeric configuration. (B) The formation of nonreducing double glycosides is unusual in that it involves the formation of two glycosidic linkages. (C) The reaction catalyzed by OtsA: the transfer of glucose, from UDP-Glucose to glucose-6-phosphate to generate trehalose-6-phosphate. T-6-P is subsequently dephosphorylated by OtsB to yield α,α-1,1 trehalose.

Figure 4.
Figure 4. Schematic Diagram of the Catalytic Center of Trehalose-6-Phosphate SynthaseSchematic diagram of the catalytic center of OtsA. Residues invariant in the active center of glycogen and maltodextrin phosphorylases are labeled in shadowed boxes. The putative donor-site glucosyl moiety (from the overlap with E. coli maltodextrin phophorylase) is included for reference. GPGTF superfamily motif elements 1 and 2 are indicated [28].

The above figures are reprinted by permission from Cell Press: Chem Biol (2002, 9, 1337-1346) copyright 2002.

Figures were selected by an automated process.