PROSITE documentation PDOC00622

Glycosyl hydrolases family 11 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 G [3] or as the glycosyl hydrolases family 11 [4,E1]. The enzymes which are currently known to belong to this family are listed below.

  • Aspergillus awamori xylanase C (xynC).
  • Bacillus circulans, pumilus, stearothermophilus and subtilis xylanase (xynA).
  • Clostridium acetobutylicum xylanase (xynB).
  • Clostridium stercorarium xylanase A (xynA).
  • Fibrobacter succinogenes xylanase C (xynC) which consist of two catalytic domains that both belong to family 10.
  • Neocallimastix patriciarum xylanase A (xynA).
  • Ruminococcus flavefaciens bifunctional xylanase XYLA (xynA). This protein consists of three domains: a N-terminal xylanase catalytic domain that belongs to family 11 of glycosyl hydrolases; a central domain composed of short repeats of Gln, Asn an Trp, and a C-terminal xylanase catalytic domain that belongs to family 10 of glycosyl hydrolases.
  • Schizophyllum commune xylanase A.
  • Streptomyces lividans xylanases B (xlnB) and C (xlnC).
  • Trichoderma reesei xylanases I and II.

Two of the conserved regions in these enzymes are centered on glutamic acid residues which have both been shown [5], in Bacillus pumilis xylanase, to be necessary for catalytic activity. We have used both regions as signature patterns.

Expert(s) to contact by email:

Henrissat B.

Last update:

April 2006 / Pattern revised.

Technical section

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

GLYCOSYL_HYDROL_F11_1, PS00776; Glycosyl hydrolases family 11 active site signature 1  (PATTERN)

GLYCOSYL_HYDROL_F11_2, PS00777; Glycosyl hydrolases family 11 active site 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

5AuthorsKo E.P., Akatsuka H., Moriyama H., Shinmyo A., Hata Y., Katsube Y., Urabe I., Okada H.
TitleSite-directed mutagenesis at aspartate and glutamate residues of xylanase from Bacillus pumilus.
SourceBiochem. J. 288:117-121(1992).
PubMed ID1359880


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