3CUY

Crystal Structure of GumK mutant D157A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.182 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structure and mechanism of GumK, a membrane-associated glucuronosyltransferase.

Barreras, M.Salinas, S.R.Abdian, P.L.Kampel, M.A.Ielpi, L.

(2008) J.Biol.Chem. 283: 25027-25035

  • DOI: 10.1074/jbc.M801227200
  • Primary Citation of Related Structures:  2HY7, 2Q6V, 3CV3

  • PubMed Abstract: 
  • Xanthomonas campestris GumK (beta-1,2-glucuronosyltransferase) is a 44-kDa membrane-associated protein that is involved in the biosynthesis of xanthan, an exopolysaccharide crucial for this bacterium's phytopathogenicity. Xanthan also has many import ...

    Xanthomonas campestris GumK (beta-1,2-glucuronosyltransferase) is a 44-kDa membrane-associated protein that is involved in the biosynthesis of xanthan, an exopolysaccharide crucial for this bacterium's phytopathogenicity. Xanthan also has many important industrial applications. The GumK enzyme is the founding member of the glycosyltransferase family 70 of carbohydrate-active enzymes, which is composed of bacterial glycosyltransferases involved in exopolysaccharide synthesis. No x-ray structures have been reported for this family. To better understand the mechanism of action of the bacterial glycosyltransferases in this family, the x-ray crystal structure of apo-GumK was solved at 1.9 angstroms resolution. The enzyme has two well defined Rossmann domains with a catalytic cleft between them, which is a typical feature of the glycosyltransferase B superfamily. Additionally, the crystal structure of GumK complexed with UDP was solved at 2.28 angstroms resolution. We identified a number of catalytically important residues, including Asp157, which serves as the general base in the transfer reaction. Residues Met231, Met273, Glu272, Tyr292, Met306, Lys307, and Gln310 interact with UDP, and mutation of these residues affected protein activity both in vitro and in vivo. The biological and structural data reported here shed light on the molecular basis for donor and acceptor selectivity in this glycosyltransferase family. These results also provide a rationale to obtain new polysaccharides by varying residues in the conserved alpha/beta/alpha structural motif of GumK.


    Organizational Affiliation

    Laboratory of Bacterial Genetics, Fundación Instituto Leloir, IIBBA-Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires C1405BWE, Argentina.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Glucuronosyltransferase GumK
A
406Xanthomonas campestris pv. campestrisGene Names: gumK
EC: 2.4.1.264
Find proteins for Q8GCH2 (Xanthomonas campestris pv. campestris)
Go to UniProtKB:  Q8GCH2
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.182 
  • Space Group: P 65 2 2
Unit Cell:
Length (Å)Angle (°)
a = 121.726α = 90.00
b = 121.726β = 90.00
c = 172.557γ = 120.00
Software Package:
Software NamePurpose
ARP/wARPmodel building
MAR345dtbdata collection
MOSFLMdata reduction
SCALAdata scaling
REFMACrefinement
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2008-04-17 
  • Released Date: 2008-07-01 
  • Deposition Author(s): Barreras, M.

Revision History 

  • Version 1.0: 2008-07-01
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance