1E6R

Chitinase B from Serratia marcescens wildtype in complex with inhibitor allosamidin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.198 

wwPDB Validation   3D Report Full Report


This is version 2.0 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 U S A 98: 8979

  • DOI: 10.1073/pnas.151103798
  • Primary Citation of Related Structures:  
    1E6R, 1E6Z, 1E6P, 1E6N

  • 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, substrate-assisted catalysis, and product displacement ...

    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:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CHITINASE B AB499Serratia marcescensMutation(s): 0 
Gene Names: chiBG5643_04810
Find proteins for Q54276 (Serratia marcescens)
Explore Q54276 
Go to UniProtKB:  Q54276
Protein Feature View
Expand
  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
MoleculeChainsChain Length2D Diagram Glycosylation3D Interactions
2-acetamido-2-deoxy-beta-D-allopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-allopyranose
C, D
2 N/A Oligosaccharides Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.198 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 55.476α = 90
b = 103.427β = 90
c = 185.01γ = 90
Software Package:
Software NamePurpose
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling
CNSphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-06-22
    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: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Other, Structure summary