4MCK

Crystal structure of Family GH19, Class IV chitinase from Zea mays


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.5 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.178 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystallographic structure of ChitA, a glycoside hydrolase family 19, plant class IV chitinase from Zea mays.

Chaudet, M.M.Naumann, T.A.Price, N.P.Rose, D.R.

(2014) Protein Sci. 23: 586-593

  • DOI: 10.1002/pro.2437

  • PubMed Abstract: 
  • Maize ChitA chitinase is composed of a small, hevein-like domain attached to a carboxy-terminal chitinase domain. During fungal ear rot, the hevein-like domain is cleaved by secreted fungal proteases to produce truncated forms of ChitA. Here, we repo ...

    Maize ChitA chitinase is composed of a small, hevein-like domain attached to a carboxy-terminal chitinase domain. During fungal ear rot, the hevein-like domain is cleaved by secreted fungal proteases to produce truncated forms of ChitA. Here, we report a structural and biochemical characterization of truncated ChitA (ChitA ΔN), which lacks the hevein-like domain. ChitA ΔN and a mutant form (ChitA ΔN-EQ) were expressed and purified; enzyme assays showed that ChitA ΔN activity was comparable to the full-length enzyme. Mutation of Glu62 to Gln (ChitA ΔN-EQ) abolished chitinase activity without disrupting substrate binding, demonstrating that Glu62 is directly involved in catalysis. A crystal structure of ChitA ΔN-EQ provided strong support for key roles for Glu62, Arg177, and Glu165 in hydrolysis, and for Ser103 and Tyr106 in substrate binding. These findings demonstrate that the hevein-like domain is not needed for enzyme activity. Moreover, comparison of the crystal structure of this plant class IV chitinase with structures from larger class I and II enzymes suggest that class IV chitinases have evolved to accommodate shorter substrates.


    Organizational Affiliation

    Department of Biology, University of Waterloo, Waterloo, Ontario, Canada, N2L 3G1.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Chitinase
A
201Zea maysEC: 3.2.1.14
Find proteins for P29022 (Zea mays)
Go to UniProtKB:  P29022
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
UNK
Query on UNK
A
L-PEPTIDE LINKINGC4 H9 N O2

--

Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.5 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.178 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 37.152α = 90.00
b = 65.167β = 90.00
c = 72.334γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data scaling
HKL-2000data reduction
PHENIXphasing
PHENIXmodel building
StructureStudiodata collection
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-03-05
    Type: Initial release
  • Version 1.1: 2014-04-02
    Type: Database references
  • Version 1.2: 2014-05-07
    Type: Database references