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PROSITE documentation PDOC00511 [for PROSITE entry PS00592]

Glycosyl hydrolases family 9 active sites signatures


The microbial degradation of cellulose and xylans requires several types of enzymes such as endoglucanases (EC, cellobiohydrolases (EC (exoglucanases), or xylanases (EC [1,2]. Fungi and bacteria produces a spectrum of cellulolytic enzymes (cellulases) and xylanases which, on the basis of sequence similarities, can be classified into families. One of these families is known as the cellulase family E [3] or as the glycosyl hydrolases family 9 [4,E1]. The enzymes which are currently known to belong to this family are listed below.

  • Butyrivibrio fibrisolvens cellodextrinase 1 (ced1).
  • Cellulomonas fimi endoglucanases B (cenB) and C (cenC).
  • Clostridium cellulolyticum endoglucanase G (celCCG).
  • Clostridium cellulovorans endoglucanase C (engC).
  • Clostridium stercoararium endoglucanase Z (avicelase I) (celZ).
  • Clostridium thermocellum endoglucanases D (celD), F (celF) and I (celI).
  • Fibrobacter succinogenes endoglucanase A (endA).
  • Pseudomonas fluorescens endoglucanase A (celA).
  • Streptomyces reticuli endoglucanase 1 (cel1).
  • Thermomonospora fusca endoglucanase E-4 (celD).
  • Dictyostelium discoideum spore germination specific endoglucanase 270-6. This slime mold enzyme may digest the spore cell wall during germination, to release the enclosed amoeba.
  • Endoglucanases from plants such as Avocado or French bean. In plants this enzyme may be involved the fruit ripening process.

Two of the most conserved regions in these enzymes are centered on conserved residues which have been shown [5,6], in the endoglucanase D from Cellulomonas thermocellum, to be important for the catalytic activity. The first region contains an active site histidine and the second region contains two catalytically important residues: an aspartate and a glutamate. We have used both regions as signature patterns.

Expert(s) to contact by email:

Henrissat B.

Last update:

November 1997 / Text revised.

Technical section

PROSITE methods (with tools and information) covered by this documentation:

GLYCOSYL_HYDROL_F9_1, PS00592; Glycosyl hydrolases family 9 active sites signature 1  (PATTERN)

GLYCOSYL_HYDROL_F9_2, PS00698; Glycosyl hydrolases family 9 active sites signature 2  (PATTERN)


1AuthorsBeguin P.
TitleMolecular biology of cellulose degradation.
SourceAnnu. Rev. Microbiol. 44:219-248(1990).
PubMed ID2252383

2AuthorsGilkes N.R. Henrissat B. Kilburn D.G. Miller R.C. Jr. Warren R.A.J.
TitleDomains in microbial beta-1, 4-glycanases: sequence conservation, function, and enzyme families.
SourceMicrobiol. Rev. 55:303-315(1991).
PubMed ID1886523

3AuthorsHenrissat B. Claeyssens M. Tomme P. Lemesle L. Mornon J.-P.
TitleCellulase families revealed by hydrophobic cluster analysis.
SourceGene 81:83-95(1989).
PubMed ID2806912

4AuthorsHenrissat B.
TitleA classification of glycosyl hydrolases based on amino acid sequence similarities.
SourceBiochem. J. 280:309-316(1991).
PubMed ID1747104

5AuthorsTomme P. Chauvaux S. Beguin P. Millet J. Aubert J.-P. Claeyssens M.
TitleIdentification of a histidyl residue in the active center of endoglucanase D from Clostridium thermocellum.
SourceJ. Biol. Chem. 266:10313-10318(1991).
PubMed ID2037583

6AuthorsTomme P. van Beeumen J. Claeyssens M.
TitleModification of catalytically important carboxy residues in endoglucanase D from Clostridium thermocellum.
SourceBiochem. J. 285:319-324(1992).
PubMed ID1637316


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