2Q1F

Crystal structure of chondroitin sulfate lyase abc from bacteroides thetaiotaomicron wal2926


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.85 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.220 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Composite active site of chondroitin lyase ABC accepting both epimers of uronic acid.

Shaya, D.Hahn, B.S.Bjerkan, T.M.Kim, W.S.Park, N.Y.Sim, J.S.Kim, Y.S.Cygler, M.

(2008) Glycobiology 18: 270-277

  • DOI: 10.1093/glycob/cwn002

  • PubMed Abstract: 
  • Enzymes have evolved as catalysts with high degrees of stereospecificity. When both enantiomers are biologically important, enzymes with two different folds usually catalyze reactions with the individual enantiomers. In rare cases a single enzyme can ...

    Enzymes have evolved as catalysts with high degrees of stereospecificity. When both enantiomers are biologically important, enzymes with two different folds usually catalyze reactions with the individual enantiomers. In rare cases a single enzyme can process both enantiomers efficiently, but no molecular basis for such catalysis has been established. The family of bacterial chondroitin lyases ABC comprises such enzymes. They can degrade both chondroitin sulfate (CS) and dermatan sulfate (DS) glycosaminoglycans at the nonreducing end of either glucuronic acid (CS) or its epimer iduronic acid (DS) by a beta-elimination mechanism, which commences with the removal of the C-5 proton from the uronic acid. Two other structural folds evolved to perform these reactions in an epimer-specific fashion: (alpha/alpha)(5) for CS (chondroitin lyases AC) and beta-helix for DS (chondroitin lyases B); their catalytic mechanisms have been established at the molecular level. The structure of chondroitinase ABC from Proteus vulgaris showed surprising similarity to chondroitinase AC, including the presence of a Tyr-His-Glu-Arg catalytic tetrad, which provided a possible mechanism for CS degradation but not for DS degradation. We determined the structure of a distantly related Bacteroides thetaiotaomicron chondroitinase ABC to identify additional structurally conserved residues potentially involved in catalysis. We found a conserved cluster located approximately 12 A from the catalytic tetrad. We demonstrate that a histidine in this cluster is essential for catalysis of DS but not CS. The enzyme utilizes a single substrate-binding site while having two partially overlapping active sites catalyzing the respective reactions. The spatial separation of the two sets of residues suggests a substrate-induced conformational change that brings all catalytically essential residues close together.


    Organizational Affiliation

    Department of Biochemistry, McGill University, Montréal, Québec, Canada.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Chondroitinase
A, B
1022Bacteroides thetaiotaomicronMutation(s): 0 
Gene Names: chonabc
EC: 4.2.2.21
Find proteins for C5G6D7 (Bacteroides thetaiotaomicron)
Go to UniProtKB:  C5G6D7
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PO4
Query on PO4

Download SDF File 
Download CCD File 
A, B
PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
CA
Query on CA

Download SDF File 
Download CCD File 
A, B
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
A, B
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.85 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.220 
  • Space Group: P 63
Unit Cell:
Length (Å)Angle (°)
a = 223.362α = 90.00
b = 223.362β = 90.00
c = 112.639γ = 120.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
DENZOdata reduction
RESOLVEphasing
REFMACrefinement
HKL-2000data reduction
SHARPphasing
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2007-05-24 
  • Released Date: 2008-01-29 
  • Deposition Author(s): Shaya, D., Cygler, M.

Revision History 

  • Version 1.0: 2008-01-29
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Advisory, Version format compliance
  • Version 1.2: 2017-10-18
    Type: Refinement description