DB code: S00204

RLCP classification 1.32.60200.73 : Hydrolysis
CATH domain 3.20.20.80 : TIM Barrel Catalytic domain
E.C. 3.2.1.17 3.2.1.14
CSA
M-CSA
MACiE

CATH domain Related DB codes (homologues)
3.20.20.80 : TIM Barrel S00202 S00210 S00748 S00906 S00907 S00911 S00912 S00915 M00134 M00160 D00479 S00205 S00206 S00207 S00203 S00208 S00209 S00211 S00213 S00214 M00113 T00307 D00165 D00166 D00169 D00176 D00501 D00502 D00503 D00844 D00861 D00864 M00026 M00112 M00193 M00346 T00057 T00062 T00063 T00066 T00067

Uniprot Enzyme Name
UniprotKB Protein name Synonyms Includes CAZy Pfam
P23472 Hevamine-A
None Chitinase
EC 3.2.1.14
Lysozyme
EC 3.2.1.17
GH18 (Glycoside Hydrolase Family 18)
PF00704 (Glyco_hydro_18)
[Graphical View]

KEGG enzyme name
lysozyme
(EC 3.2.1.17 )
muramidase
(EC 3.2.1.17 )
globulin G
(EC 3.2.1.17 )
mucopeptide glucohydrolase
(EC 3.2.1.17 )
globulin G1
(EC 3.2.1.17 )
N,O-diacetylmuramidase
(EC 3.2.1.17 )
lysozyme g
(EC 3.2.1.17 )
L-7001
(EC 3.2.1.17 )
1,4-N-acetylmuramidase
(EC 3.2.1.17 )
mucopeptide N-acetylmuramoylhydrolase
(EC 3.2.1.17 )
PR1-lysozyme
(EC 3.2.1.17 )
chitinase
(EC 3.2.1.14 )
chitodextrinase
(EC 3.2.1.14 )
1,4-beta-poly-N-acetylglucosaminidase
(EC 3.2.1.14 )
poly-beta-glucosaminidase
(EC 3.2.1.14 )
beta-1,4-poly-N-acetyl glucosamidinase
(EC 3.2.1.14 )
poly[1,4-(N-acetyl-beta-D-glucosaminide)] glycanohydrolase
(EC 3.2.1.14 )

UniprotKB: Accession Number Entry name Activity Subunit Subcellular location Cofactor
P23472 CHLY_HEVBR Random hydrolysis of N-acetyl-beta-D- glucosaminide (1->4)-beta-linkages in chitin and chitodextrins. Hydrolysis of (1->4)-beta-linkages between N- acetylmuramic acid and N-acetyl-D-glucosamine residues in a peptidoglycan and between N-acetyl-D-glucosamine residues in chitodextrins. Vacuole. Note=In the lutoids (vacuoles) from rubber latex.

KEGG Pathways
Map code Pathways E.C.
MAP00530 Aminosugars metabolism 3.2.1.14

Compound table
Substrates Products Intermediates
KEGG-id C00889 C00461 C00851 C00001 C04394 C00851 C03518 C00140
E.C. 3.2.1.17
3.2.1.14
3.2.1.17
3.2.1.14
3.2.1.17
3.2.1.14
3.2.1.17
3.2.1.17
3.2.1.14
3.2.1.17
3.2.1.14
Compound Peptidoglycan Chitin Chitodextrin H2O Peptidoglycan(N-acetyl-D-glucosamine) Chitodextrin N-Acetyl-D-glucosaminide N-Acetyl-D-glucosamine
Type amide group,amine group,peptide/protein,polysaccharide amide group,polysaccharide amide group,polysaccharide H2O amino acids,amide group,amine group,carbohydrate,lipid,peptide/protein,polysaccharide amide group,polysaccharide amide group,carbohydrate amide group,carbohydrate
ChEBI 15377
 15377
 		8006
 8006
 		506227
 506227
PubChem 22247451
 962
 22247451
 962
 		5462260
 5462260
 		439174
 439174
1hvmA Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1hvqA Unbound Unbound Unbound Unbound Bound:NAG-NAG-NAG Unbound Unbound Unbound
1lloA Unbound Unbound Unbound Unbound Unbound Unbound Unbound Intermediate-analogue:NAA-NAA-AMI
2hvmA Unbound Unbound Unbound Unbound Unbound Unbound Unbound Unbound

Reference for Active-site residues
resource references E.C.
Swiss-prot

Active-site residues
PDB Catalytic residues Cofactor-binding residues Modified residues Main-chain involved in catalysis Comment
1hvmA ASP 125;GLU 127;TYR 183
1hvqA ASP 125;GLU 127;TYR 183
1lloA ASP 125;GLU 127;TYR 183
2hvmA ASP 125;GLU 127;TYR 183

References for Catalytic Mechanism
References Sections No. of steps in catalysis
[2]
Fig.2, Fig.3C, p.15621-15623
[5]
Fig.4, p.898-900

References
[1]
Resource
Comments X-ray crystallography (2.2 Angstroms)
Medline ID 95219380
PubMed ID 7704528
Journal Structure
Year 1994
Volume 2
Pages 1181-89
Authors Terwisscha van Scheltinga AC, Kalk KH, Beintema JJ, Dijkstra BW
Title Crystal structures of hevamine, a plant defence protein with chitinase and lysozyme activity, and its complex with an inhibitor.
Related PDB 1hvq
Related UniProtKB P23472
[2]
Resource
Comments X-ray crystallography (1.85 Angstroms)
Medline ID 96096984
PubMed ID 7495789
Journal Biochemistry
Year 1995
Volume 34
Pages 15619-23
Authors Terwisscha van Scheltinga AC, Armand S, Kalk KH, Isogai A, Henrissat B, Dijkstra BW
Title Stereochemistry of chitin hydrolysis by a plant chitinase/lysozyme and X-ray structure of a complex with allosamidin: evidence for substrate assisted catalysis.
Related PDB 1llo
Related UniProtKB P23472
[3]
Resource
Comments X-ray crystallography (1.8 Angstroms)
Medline ID 96428689
PubMed ID 8831791
Journal J Mol Biol
Year 1996
Volume 262
Pages 243-57
Authors Terwisscha van Scheltinga AC, Hennig M, Dijkstra BW
Title The 1.8 A resolution structure of hevamine, a plant chitinase/lysozyme, and analysis of the conserved sequence and structure motifs of glycosyl hydrolase family 18.
Related PDB 1hvm 2hvm
Related UniProtKB P23472
[4]
Resource
Comments Clustering of structures
Medline ID
PubMed ID 11742103
Journal Protein Eng
Year 2001
Volume 14
Pages 845-55
Authors Nagano N, Porter CT, Thornton JM
Title The (betaalpha)(8) glycosidases: sequence and structure analyses suggest distant evolutionary relationships.
Related PDB
Related UniProtKB
[5]
Resource
Comments X-ray crystallography of active site mutants
Medline ID
PubMed ID 11846790
Journal Eur J Biochem
Year 2002
Volume 269
Pages 893-901
Authors Bokma E, Rozeboom HJ, Sibbald M, Dijkstra BW, Beintema JJ
Title Expression and characterization of active site mutants of hevamine, a chitinase from the rubber tree Hevea brasiliensis.
Related PDB
Related UniProtKB

Comments
This family belongs to glycosidase family-18, which has a retaining mechanism.
According to the literature [2], N-acetyl group of the substrate act as a nucleophile, which will form intramolecular covalent bond within the substrate. Glu127 acts as a general acid or proton donor, which can protonate the O4 atom of the sugar at subsite (+1).
The literature [2] also reported that the conserved residues, Asp125 and Tyr183, interact with the oxygen atom of the oxazoline intermediate. Thus, these residues can function as stabilizers.

Created Updated
2002-11-01 2009-02-26