3W4R

Crystal structure of an insect chitinase from the Asian corn borer, Ostrinia furnacalis


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.7 Å
  • R-Value Free: 0.159 
  • R-Value Work: 0.147 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structural characteristics of an insect group I chitinase, an enzyme indispensable to moulting

Chen, L.Liu, T.Zhou, Y.Chen, Q.Shen, X.Yang, Q.

(2014) Acta Crystallogr.,Sect.D 70: 932-942

  • DOI: 10.1107/S1399004713033841
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Insects possess a greater number of chitinases than any other organisms. This work is the first report of unliganded and oligosaccharide-complexed crystal structures of the insect chitinase OfChtI from Ostrinia furnacalis, which is essential to moult ...

    Insects possess a greater number of chitinases than any other organisms. This work is the first report of unliganded and oligosaccharide-complexed crystal structures of the insect chitinase OfChtI from Ostrinia furnacalis, which is essential to moulting. The obtained crystal structures were solved at resolutions between 1.7 and 2.2 Å. A structural comparison with other chitinases revealed that OfChtI contains a long substrate-binding cleft similar to the bacterial chitinase SmChiB from Serratia marcescens. However, unlike the exo-acting SmChiB, which has a blocked and tunnel-like cleft, OfChtI possesses an open and groove-like cleft. The complexed structure of the catalytic domain of OfChtI (OfChtI-CAD) with (GlcNAc)2/3 indicates that the reducing sugar at subsite -1 is in an energetically unfavoured `boat' conformation, a state that possibly exists just before the completion of catalysis. Because OfChtI is known to act from nonreducing ends, (GlcNAc)3 would be a hydrolysis product of (GlcNAc)6, suggesting that OfChtI possesses an endo enzymatic activity. Furthermore, a hydrophobic plane composed of four surface-exposed aromatic residues is adjacent to the entrance to the substrate-binding cleft. Mutations of these residues greatly impair the chitin-binding activity, indicating that this hydrophobic plane endows OfChtI-CAD with the ability to anchor chitin. This work reveals the unique structural characteristics of an insect chitinase.


    Organizational Affiliation

    School of Life Science and Biotechnology, Dalian University of Technology, 2 Linggong Road, Dalian, Liaoning 116024, People's Republic of China.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Chitinase
A
554Ostrinia furnacalisMutation(s): 0 
EC: 3.2.1.14
Find proteins for Q2V6H4 (Ostrinia furnacalis)
Go to UniProtKB:  Q2V6H4
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NAG
Query on NAG

Download SDF File 
Download CCD File 
A
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.7 Å
  • R-Value Free: 0.159 
  • R-Value Work: 0.147 
  • Space Group: P 65
Unit Cell:
Length (Å)Angle (°)
a = 93.761α = 90.00
b = 93.761β = 90.00
c = 121.964γ = 120.00
Software Package:
Software NamePurpose
HKL-2000data collection
PHASERphasing
PHENIXrefinement
HKL-2000data scaling
HKL-2000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-02-12
    Type: Initial release
  • Version 1.1: 2014-05-07
    Type: Database references