1E6R

Chitinase B from Serratia marcescens wildtype in complex with inhibitor allosamidin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.198 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural Insights Into the Catalytic Mechanism of a Family 18 Exo-Chitinase

Van Aalten, D.M.F.Komander, D.Synstad, B.Gseidnes, S.Peter, M.G.Eijsink, V.G.H.

(2001) Proc.Natl.Acad.Sci.USA 98: 8979

  • DOI: 10.1073/pnas.151103798
  • Primary Citation of Related Structures:  1E6N, 1E6P, 1E6Z
  • Also Cited By: 1GOI, 1OGB, 1OGG, 1UR8, 1UR9

  • PubMed Abstract: 
  • Chitinase B (ChiB) from Serratia marcescens is a family 18 exo-chitinase whose catalytic domain has a TIM-barrel fold with a tunnel-shaped active site. We have solved structures of three ChiB complexes that reveal details of substrate binding, substr ...

    Chitinase B (ChiB) from Serratia marcescens is a family 18 exo-chitinase whose catalytic domain has a TIM-barrel fold with a tunnel-shaped active site. We have solved structures of three ChiB complexes that reveal details of substrate binding, substrate-assisted catalysis, and product displacement. The structure of an inactive ChiB mutant (E144Q) complexed with a pentameric substrate (binding in subsites -2 to +3) shows closure of the "roof" of the active site tunnel. It also shows that the sugar in the -1 position is distorted to a boat conformation, thus providing structural evidence in support of a previously proposed catalytic mechanism. The structures of the active enzyme complexed to allosamidin (an analogue of a proposed reaction intermediate) and of the active enzyme soaked with pentameric substrate show events after cleavage of the glycosidic bond. The latter structure shows reopening of the roof of the active site tunnel and enzyme-assisted product displacement in the +1 and +2 sites, allowing a water molecule to approach the reaction center. Catalysis is accompanied by correlated structural changes in the core of the TIM barrel that involve conserved polar residues whose functions were hitherto unknown. These changes simultaneously contribute to stabilization of the reaction intermediate and alternation of the pKa of the catalytic acid during the catalytic cycle.


    Organizational Affiliation

    Wellcome Trust Biocentre, Department of Biochemistry, University of Dundee, Dundee DD1 5EH, Scotland. dava@davapc1.bioch.dundee.ac.uk




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CHITINASE B
A, B
499Serratia marcescensGene Names: chiB
Find proteins for Q54276 (Serratia marcescens)
Go to UniProtKB:  Q54276
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A, B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
NAA
Query on NAA

Download SDF File 
Download CCD File 
A, B
N-ACETYL-D-ALLOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-UIAUGNHASA-N
 Ligand Interaction
AMI
Query on AMI

Download SDF File 
Download CCD File 
A, B
ALLOSAMIZOLINE
C9 H16 N2 O4
MKJAYSJDHSEFRI-PVFLNQBWSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.198 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 55.476α = 90.00
b = 103.427β = 90.00
c = 185.010γ = 90.00
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
CNSphasing
CNSrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-06-22
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance