2D05

Chitosanase From Bacillus circulans mutant K218P


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.173 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Bacillus circulans MH-K1 Chitosanase: Amino Acid Residues Responsible for Substrate Binding

Fukamizo, T.Amano, S.Yamaguchi, K.Yoshikawa, T.Katsumi, T.Saito, J.Suzuki, M.Miki, K.Nagata, Y.Ando, A.

(2005) J.Biochem.(Tokyo) 138: 563-569

  • DOI: 10.1093/jb/mvi156

  • PubMed Abstract: 
  • To identify the amino acids responsible for the substrate binding of chitosanase from Bacillus circulans MH-K1 (MH-K1 chitosanase), Tyr148 and Lys218 of the chitosanase were mutated to serine and proline, respectively, and the mutated chitosanases we ...

    To identify the amino acids responsible for the substrate binding of chitosanase from Bacillus circulans MH-K1 (MH-K1 chitosanase), Tyr148 and Lys218 of the chitosanase were mutated to serine and proline, respectively, and the mutated chitosanases were characterized. The enzymatic activities of Y148S and K218P were found to be 12.5% and 0.16% of the wild type, respectively. When the (GlcN)3 binding ability to the chitosanase was evaluated by fluorescence spectroscopy and thermal unfolding experiments, the binding abilities of both mutant enzymes were markedly reduced as compared with the wild type enzyme. The affinity of the enzyme for the trisaccharide decreased by 1.0 kcal/mol of binding free energy for Y148S, and 3.7 kcal/mol for K218P. The crystal structure of K218P revealed that Pro218 forms a cis-peptide bond and that the state of the flexible loop containing the 218th residue is considerably affected by the mutation. Thus, we conclude that the flexible loop containing Lys218 plays an important role in substrate binding, and that the role of Tyr148 is less critical, but still important, due to a stacking interaction or hydrogen bond.


    Related Citations: 
    • Crystal structure of chitosanase from Bacillus circulans MH-K1 at 1.6-A resolution and its substrate recognition mechanism
      Saito, J.,Kita, A.,Higuchi, Y.,Nagata, Y.,Ando, A.,Miki, K.
      (1999) J.Biol.Chem. 274: 30818
    • Crystallization and preliminary X-ray crystallographic analysis of chitosanase from Bacillus circulans MH-K1
      Saito, J.I.,Nagata, Y.,Ando, A.,Kita, A.,Miki, K.
      (1995) ACTA CRYSTALLOGR.,SECT.D 51: 856


    Organizational Affiliation

    Department of Advanced Bioscience, Kinki University, 3327-204 Nakamachi, Nara 631-8505. fukamizo@nara.kindai.ac.jp




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Chitosanase
A
259Bacillus circulansMutations: P218K
Gene Names: csn
EC: 3.2.1.132
Find proteins for P33673 (Bacillus circulans)
Go to UniProtKB:  P33673
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.173 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 43.300α = 90.00
b = 128.100β = 90.00
c = 57.800γ = 90.00
Software Package:
Software NamePurpose
AMoREphasing
X-PLORrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-12-06
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance