DB code: S00265

RLCP classification 1.30.300.2 : Hydrolysis
CATH domain 1.10.530.40 : Lysozyme Catalytic domain
E.C. 3.2.1.132
CSA 1chk
M-CSA 1chk
MACiE

CATH domain Related DB codes (homologues)
1.10.530.40 : Lysozyme S00021

Uniprot Enzyme Name
UniprotKB Protein name Synonyms CAZy Pfam
P33673 Chitosanase
EC 3.2.1.132
GH46 (Glycoside Hydrolase Family 46)
PF01374 (Glyco_hydro_46)
[Graphical View]
P33665 Chitosanase
EC 3.2.1.132
GH46 (Glycoside Hydrolase Family 46)
PF01374 (Glyco_hydro_46)
[Graphical View]

KEGG enzyme name
chitosanase

UniprotKB: Accession Number Entry name Activity Subunit Subcellular location Cofactor
P33673 CHIS_BACCI Endohydrolysis of beta-(1->4)-linkages between D-glucosamine residues in a partly acetylated chitosan. Secreted.
P33665 CHIS_STRSN Endohydrolysis of beta-(1->4)-linkages between D-glucosamine residues in a partly acetylated chitosan. Secreted.

KEGG Pathways
Map code Pathways E.C.
MAP00530 Aminosugars metabolism

Compound table
Substrates Products Intermediates
KEGG-id C00734 C00001 C00734 C06023
E.C.
Compound Chitosan H2O Chitosan D-Glucosaminide
Type amine group,polysaccharide H2O amine group,polysaccharide amine group,polysaccharide
ChEBI 15377
PubChem 3086191
22247451
962
3086191
3086191
1chkA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound
1chkB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound
1qgiA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Analogue:GCS-GCS-NAG Unbound Unbound

Reference for Active-site residues
resource references E.C.
Swiss-prot;P33665, P33673 & literature [4], [6]

Active-site residues
PDB Catalytic residues Cofactor-binding residues Modified residues Main-chain involved in catalysis Comment
1chkA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain GLU 22;ASP 40
1chkB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain GLU 22;ASP 40
1qgiA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain GLU 37;ASP 55

References for Catalytic Mechanism
References Sections No. of steps in catalysis
[4]
Fig.7, p.158-160
[6]
Fig.2, p.690-691

References
[1]
Resource
Comments CHARACTERIZATION.
Medline ID 96033029
PubMed ID 7487871
Journal Biochem J
Year 1995
Volume 311
Pages 377-83
Authors Fukamizo T, Honda Y, Goto S, Boucher I, Brzezinski R
Title Reaction mechanism of chitosanase from Streptomyces sp. N174.
Related PDB
Related UniProtKB P33665
[2]
Resource
Comments MUTAGENESIS.
Medline ID 96125086
PubMed ID 8537367
Journal J Biol Chem
Year 1995
Volume 270
Pages 31077-82
Authors Boucher I, Fukamizo T, Honda Y, Willick GE, Neugebauer WA, Brzezinski R
Title Site-directed mutagenesis of evolutionary conserved carboxylic amino acids in the chitosanase from Streptomyces sp. N174 reveals two residues essential for catalysis.
Related PDB
Related UniProtKB P33665
[3]
Resource
Comments
Medline ID
PubMed ID 8535779
Journal Structure
Year 1995
Volume 3
Pages 853-9
Authors Davies G, Henrissat B
Title Structures and mechanisms of glycosyl hydrolases.
Related PDB
Related UniProtKB
[4]
Resource
Comments X-RAY CRYSTALLOGRAPHY (2.4 ANGSTROMS).
Medline ID 96163435
PubMed ID 8564542
Journal Nat Struct Biol
Year 1996
Volume 3
Pages 155-62
Authors Marcotte EM, Monzingo AF, Ernst SR, Brzezinski R, Robertus JD
Title X-ray structure of an anti-fungal chitosanase from streptomyces N174.
Related PDB 1chk
Related UniProtKB P33665
[5]
Resource
Comments
Medline ID
PubMed ID 8564539
Journal Nat Struct Biol
Year 1996
Volume 3
Pages 133-40
Authors Monzingo AF, Marcotte EM, Hart PJ, Robertus JD
Title Chitinases, chitosanases, and lysozymes can be divided into procaryotic and eucaryotic families sharing a conserved core.
Related PDB
Related UniProtKB
[6]
Resource
Comments
Medline ID
PubMed ID 9599657
Journal Biochem Cell Biol
Year 1997
Volume 75
Pages 687-96
Authors Fukamizo T, Brzezinski R
Title Chitosanase from Streptomyces sp. strain N174: a comparative review of its structure and function.
Related PDB
Related UniProtKB
[7]
Resource
Comments
Medline ID
PubMed ID 9989221
Journal Biochim Biophys Acta
Year 1999
Volume 1429
Pages 365-76
Authors Honda Y, Fukamizo T, Okajima T, Goto S, Boucher I, Brzezinski R
Title Thermal unfolding of chitosanase from Streptomyces sp. N174: role of tryptophan residues in the protein structure stabilization.
Related PDB
Related UniProtKB
[8]
Resource
Comments STRAIN=MH-K1;
Medline ID 99452978
PubMed ID 10521473
Journal J Biol Chem
Year 1999
Volume 274
Pages 30818-25
Authors Saito J, Kita A, Higuchi Y, Nagata Y, Ando A, Miki K
Title Crystal structure of chitosanase from Bacillus circulans MH-K1 at 1.6-A resolution and its substrate recognition mechanism.
Related PDB 1qgi
Related UniProtKB P33673
[9]
Resource
Comments
Medline ID
PubMed ID 12369923
Journal Curr Protein Pept Sci
Year 2000
Volume 1
Pages 105-24
Authors Fukamizo T
Title Chitinolytic enzymes: catalysis, substrate binding, and their application.
Related PDB
Related UniProtKB
[10]
Resource
Comments
Medline ID
PubMed ID 10829022
Journal J Biol Chem
Year 2000
Volume 275
Pages 25633-40
Authors Fukamizo T, Juffer AH, Vogel HJ, Honda Y, Tremblay H, Boucher I, Neugebauer WA, Brzezinski R
Title Theoretical calculation of pKa reveals an important role of Arg205 in the activity and stability of Streptomyces sp. N174 chitosanase.
Related PDB
Related UniProtKB
[11]
Resource
Comments
Medline ID
PubMed ID 11499927
Journal Appl Microbiol Biotechnol
Year 2001
Volume 56
Pages 173-80
Authors Yoon HG, Kim HY, Lim YH, Kim HK, Shin DH, Hong BS, Cho HY
Title Identification of essential amino acid residues for catalytic activity and thermostability of novel chitosanase by site-directed mutagenesis.
Related PDB
Related UniProtKB
[12]
Resource
Comments
Medline ID
PubMed ID 12092850
Journal Biosci Biotechnol Biochem
Year 2002
Volume 66
Pages 986-95
Authors Yoon HG, Lee KH, Kim HY, Kim HK, Shin DH, Hong BS, Cho HY
Title Gene cloning and biochemical analysis of thermostable chitosanase (TCH-2) from Bacillus coagulans CK108.
Related PDB
Related UniProtKB
[13]
Resource
Comments
Medline ID
PubMed ID 11754739
Journal J Biochem (Tokyo)
Year 2002
Volume 131
Pages 87-96
Authors Shimono K, Shigeru K, Tsuchiya A, Itou N, Ohta Y, Tanaka K, Nakagawa T, Matsuda H, Kawamukai M
Title Two glutamic acids in chitosanase A from Matsuebacter chitosanotabidus 3001 are the catalytically important residues.
Related PDB
Related UniProtKB

Comments
This enzyme belongs to the glycosidase family-46, with an inverting mechanism.
According to the literature [4] & [6], the catalytic reaction proceeds by an SN2 mechanism, as follows:
(1) Asp40 (of PDB;1chk) acts as a general base, which activates a water molecule to attack on the C1 atom of the glycoside bond to be cleaved. Here, the sugar can distort to a half-chair configuration for the nucleophilic attack.
(2) At the same time, Glu22 acts as a general acid to protonate the leaving group, which facilitate the nucleophilic attack by the water.

Created Updated
2005-03-23 2009-02-26