3ALF

Crystal Structure of Class V Chitinase from Nicotiana tobaccum


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.20 Å
  • R-Value Free: 0.187 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.176 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Crystal structure and mode of action of a class V chitinase from Nicotiana tabacum

Ohnuma, T.Numata, T.Osawa, T.Mizuhara, M.Varum, K.M.Fukamizo, T.

(2011) Plant Mol Biol 75: 291-304

  • DOI: https://doi.org/10.1007/s11103-010-9727-z
  • Primary Citation of Related Structures:  
    3ALF, 3ALG

  • PubMed Abstract: 

    A class V chitinase from Nicotiana tabacum (NtChiV) with amino acid sequence similar to that of Serratia marcescens chitinase B (SmChiB) was expressed in E. coli and purified to homogeneity. When N-acetylglucosamine oligosaccharides [(NAG)(n)] were hydrolyzed by the purified NtChiV, the second glycosidic linkage from the non-reducing end was predominantly hydrolyzed in a manner similar to that of SmChiB. NtChiV was shown to hydrolyze partially N-acetylated chitosan non-processively, whereas SmChiB hydrolyzes the same substrate processively. The crystal structure of NtChiV was determined by the single-wavelength anomalous dispersion method at 1.2 Å resolution. The protein adopts a classical (β/α)₈-barrel fold (residues 1-233 and 303-348) with an insertion of a small (α + β) domain (residues 234-302). This is the first crystal structure of a plant class V chitinase. The crystal structure of the inactive mutant NtChiV E115Q complexed with (NAG)₄ was also solved and exhibited a linear conformation of the bound oligosaccharide occupying -2, +1, +2, and +3 subsites. The complex structure corresponds to an initial state of (NAG)₄ binding, which is proposed to be converted into a bent conformation through sliding of the +1, +2, and +3 sugar units to -1, +1, and +2 subsites. Although NtChiV is similar to SmChiB, the chitin-binding domain is present in the C-terminus of the latter, but not in the former. Aromatic amino acid residues found in the substrate binding cleft of SmChiB, including Trp97, are substituted with aliphatic residues in NtChiV. These structural differences appear to be responsible for NtChiV being a non-processive enzyme.


  • Organizational Affiliation

    Department of Advanced Bioscience, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Chitinase, class V353Nicotiana tabacumMutation(s): 0 
Gene Names: chi-V
EC: 3.2.1.14
UniProt
Find proteins for Q43576 (Nicotiana tabacum)
Explore Q43576 
Go to UniProtKB:  Q43576
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ43576
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.20 Å
  • R-Value Free: 0.187 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.176 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 62.395α = 90
b = 120.292β = 90
c = 51.912γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
SHARPphasing
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-03-23
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2024-03-13
    Changes: Data collection, Database references, Derived calculations