2XVM

Crystal structure of the tellurite detoxification protein TehB from E. coli in complex with SAH


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.48 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.170 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure and Mechanism of the Chalcogen Detoxifying Protein Tehb from Escherichia Coli.

Choudhury, H.G.Cameron, A.D.Iwata, S.Beis, K.

(2011) Biochem.J. 435: 85

  • DOI: 10.1042/BJ20102014
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The oxyanion derivatives of the chalcogens tellurium and selenium are toxic to living organisms even at very low levels. Bacteria have developed mechanisms to overcome their toxicity by methylating them. The structure of TehB from Escherichia coli ha ...

    The oxyanion derivatives of the chalcogens tellurium and selenium are toxic to living organisms even at very low levels. Bacteria have developed mechanisms to overcome their toxicity by methylating them. The structure of TehB from Escherichia coli has been determined in the presence of the cofactor analogues SAH (S-adenosylhomocysteine) and sinefungin (a non-hydrolysable form of S-adenosyl-L-methionine) at 1.48 Å (1 Å=0.1 nm) and 1.9 Å respectively. Interestingly, our kinetic data show that TehB does not discriminate between selenium or tellurite oxyanions, making it a very powerful detoxifying protein. Analysis of the active site has identified three conserved residues that are capable of binding and orientating the metals for nucleophilic attack: His176, Arg177 and Arg184. Mutagenesis studies revealed that the H176A and R184A mutants retained most of their activity, whereas the R177A mutant had 65% of its activity abolished. Based on the structure and kinetic data we propose an SN2 nucleophilic attack reaction mechanism. These data provide the first molecular understanding of the detoxification of chalcogens by bacteria.


    Organizational Affiliation

    Membrane Protein Laboratory, Imperial College London, Diamond Light Source, Chilton, Oxfordshire OX11 0DE, UK.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
TELLURITE RESISTANCE PROTEIN TEHB
A, B
199Escherichia coli (strain K12)Mutation(s): 1 
Gene Names: tehB
EC: 2.1.1.265
Find proteins for P25397 (Escherichia coli (strain K12))
Go to UniProtKB:  P25397
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SAH
Query on SAH

Download SDF File 
Download CCD File 
A, B
S-ADENOSYL-L-HOMOCYSTEINE
C14 H20 N6 O5 S
ZJUKTBDSGOFHSH-WFMPWKQPSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.48 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.170 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 130.362α = 90.00
b = 55.644β = 97.72
c = 59.420γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
REFMACrefinement
XDSdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-02-16
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance