2CJL

CRYSTAL STRUCTURE AND ENZYMATIC PROPERTIES OF A BACTERIAL FAMILY 19 CHITINASE REVEAL DIFFERENCES WITH PLANT ENZYMES


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.187 
  • R-Value Observed: 0.188 

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This is version 1.2 of the entry. See complete history


Literature

Crystal Structure and Enzymatic Properties of a Bacterial Family 19 Chitinase Reveal Differences with Plant Enzymes

Hoell, I.A.Dalhus, B.Heggset, E.B.Aspmo, S.I.Eijsink, V.G.H.

(2006) FEBS J 273: 4889

  • DOI: 10.1111/j.1742-4658.2006.05487.x
  • Primary Citation of Related Structures:  
    2CJL

  • PubMed Abstract: 
  • We describe the cloning, overexpression, purification, characterization and crystal structure of chitinase G, a single-domain family 19 chitinase from the Gram-positive bacterium Streptomyces coelicolor A3(2). Although chitinase G was not capable of releasing 4-methylumbelliferyl from artificial chitooligosaccharide substrates, it was capable of degrading longer chitooligosaccharides at rates similar to those observed for other chitinases ...

    We describe the cloning, overexpression, purification, characterization and crystal structure of chitinase G, a single-domain family 19 chitinase from the Gram-positive bacterium Streptomyces coelicolor A3(2). Although chitinase G was not capable of releasing 4-methylumbelliferyl from artificial chitooligosaccharide substrates, it was capable of degrading longer chitooligosaccharides at rates similar to those observed for other chitinases. The enzyme was also capable of degrading a colored colloidal chitin substrate (carboxymethyl-chitin-remazol-brilliant violet) and a small, presumably amorphous, subfraction of alpha-chitin and beta-chitin, but was not capable of degrading crystalline chitin completely. The crystal structures of chitinase G and a related Streptomyces chitinase, chitinase C [Kezuka Y, Ohishi M, Itoh Y, Watanabe J, Mitsutomi M, Watanabe T & Nonaka T (2006) J Mol Biol358, 472-484], showed that these bacterial family 19 chitinases lack several loops that extend the substrate-binding grooves in family 19 chitinases from plants. In accordance with these structural features, detailed analysis of the degradation of chitooligosaccharides by chitinase G showed that the enzyme has only four subsites (- 2 to + 2), as opposed to six (- 3 to + 3) for plant enzymes. The most prominent structural difference leading to reduced size of the substrate-binding groove is the deletion of a 13-residue loop between the two putatively catalytic glutamates. The importance of these two residues for catalysis was confirmed by a site-directed mutagenesis study.


    Organizational Affiliation

    Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1432 As, Norway.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
SECRETED CHITINASEA, B204Streptomyces coelicolorMutation(s): 0 
EC: 3.2.1.14
UniProt
Find proteins for Q8CK55 (Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145))
Explore Q8CK55 
Go to UniProtKB:  Q8CK55
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8CK55
Protein Feature View
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  • Reference Sequence
Small Molecules
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.50 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.187 
  • R-Value Observed: 0.188 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 48.671α = 90
b = 74.378β = 108.57
c = 64.179γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling
MOLREPphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-10-04
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance