Maltosyltransferase from Thermotoga maritima

Experimental Data Snapshot

  • Resolution: 2.40 Å
  • R-Value Free: 0.263 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.208 

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The Crystal Structure of Thermotoga Maritima Maltosyltransferase and its Implications for the Molecular Basis of the Novel Transfer Specificity

Roujeinikova, A.Raasch, C.Burke, J.Baker, P.J.Liebl, W.Rice, D.W.

(2001) J Mol Biol 312: 119

  • DOI: https://doi.org/10.1006/jmbi.2001.4944
  • Primary Citation of Related Structures:  
    1GJU, 1GJW

  • PubMed Abstract: 

    Maltosyltransferase (MTase) from the hyperthermophile Thermotoga maritima represents a novel maltodextrin glycosyltransferase acting on starch and malto-oligosaccharides. It catalyzes the transfer of maltosyl units from alpha-1,4-linked glucans or malto-oligosaccharides to other alpha-1,4-linked glucans, malto-oligosaccharides or glucose. It belongs to the glycoside hydrolase family 13, which represents a large group of (beta/alpha)(8) barrel proteins sharing a similar active site structure. The crystal structures of MTase and its complex with maltose have been determined at 2.4 A and 2.1 A resolution, respectively. MTase is a homodimer, each subunit of which consists of four domains, two of which are structurally homologous to those of other family 13 enzymes. The catalytic core domain has the (beta/alpha)(8) barrel fold with the active-site cleft formed at the C-terminal end of the barrel. Substrate binding experiments have led to the location of two distinct maltose-binding sites; one lies in the active-site cleft, covering subsites -2 and -1; the other is located in a pocket adjacent to the active-site cleft. The structure of MTase, together with the conservation of active-site residues among family 13 glycoside hydrolases, are consistent with a common double-displacement catalytic mechanism for this enzyme. Analysis of maltose binding in the active site reveals that the transfer of dextrinyl residues longer than a maltosyl unit is prevented by termination of the active-site cleft after the -2 subsite by the side-chain of Lys151 and the stretch of residues 314-317, providing an explanation for the strict transfer specificity of MTase.

  • Organizational Affiliation

    Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, S10 2TN, England.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
MALTODEXTRIN GLYCOSYLTRANSFERASE637Thermotoga maritima MSB8Mutation(s): 0 
Find proteins for O33838 (Thermotoga maritima)
Explore O33838 
Go to UniProtKB:  O33838
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO33838
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.40 Å
  • R-Value Free: 0.263 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.208 
  • Space Group: P 41 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 148.74α = 90
b = 148.74β = 90
c = 106.7γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-09-06
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 2.0: 2019-05-22
    Changes: Atomic model, Data collection, Other, Refinement description