1CHK

STREPTOMYCES N174 CHITOSANASE PH5.5 298K


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.175 
  • R-Value Work: 0.181 
  • R-Value Observed: 0.181 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

X-ray structure of an anti-fungal chitosanase from streptomyces N174.

Marcotte, E.M.Monzingo, A.F.Ernst, S.R.Brzezinski, R.Robertus, J.D.

(1996) Nat Struct Biol 3: 155-162

  • DOI: 10.1038/nsb0296-155
  • Primary Citation of Related Structures:  
    1CHK

  • PubMed Abstract: 
  • We report the 2.4 A X-ray crystal structure of a protein with chitosan endo-hydrolase activity isolated from Streptomyces N174. The structure was solved using phases acquired by SIRAS from a two-site methyl mercury derivative combined with solvent flattening and non-crystallographic two-fold symmetry averaging, and refined to an R-factor of 18 ...

    We report the 2.4 A X-ray crystal structure of a protein with chitosan endo-hydrolase activity isolated from Streptomyces N174. The structure was solved using phases acquired by SIRAS from a two-site methyl mercury derivative combined with solvent flattening and non-crystallographic two-fold symmetry averaging, and refined to an R-factor of 18.5%. The mostly alpha-helical fold reveals a structural core shared with several classes of lysozyme and barley endochitinase, in spite of a lack of shared sequence. Based on this structural similarity we postulate a putative active site, mechanism of action and mode of substrate recognition. It appears that Glu 22 acts as an acid and Asp 40 serves as a general base to activate a water molecule for an SN2 attack on the glycosidic bond. A series of amino-acid side chains and backbone carbonyl groups may bind the polycationic chitosan substrate in a deep electronegative binding cleft.


    Related Citations: 
    • Crystallization of a Chitosanase from Streptomyces N174
      Marcotte, E., Hart, P.J., Boucher, I., Brzezinski, R., Robertus, J.D.
      (1993) J Mol Biol 232: 995

    Organizational Affiliation

    Department of Chemistry and Biochemistry, University of Texas, Austin 78712, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CHITOSANASEA, B238Streptomyces sp. N174Mutation(s): 0 
Gene Names: csnchs
EC: 3.2.1.132
UniProt
Find proteins for P33665 (Streptomyces sp. (strain N174))
Explore P33665 
Go to UniProtKB:  P33665
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.175 
  • R-Value Work: 0.181 
  • R-Value Observed: 0.181 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 56.3α = 90
b = 59.3β = 96.2
c = 85.4γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
SDMSdata reduction
SDMSdata scaling
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1996-07-11
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Source and taxonomy, Version format compliance