PROSITE documentation PDOC00621
Glycosyl hydrolases family 3 active site


It has been shown [1,2] that the following glycosyl hydrolases can be, on the basis of sequence similarities, classified into a single family:

  • β glucosidases (EC from the fungi Aspergillus wentii (A-3), Hansenula anomala, Kluyveromyces fragilis, Saccharomycopsis fibuligera, (BGL1 and BGL2), Schizophyllum commune and Trichoderma reesei (BGL1).
  • β glucosidases from the bacteria Agrobacterium tumefaciens (Cbg1), Butyrivibrio fibrisolvens (bglA), Clostridium thermocellum (bglB), Escherichia coli (bglX), Erwinia chrysanthemi (bgxA) and Ruminococcus albus.
  • Alteromonas strain O-7 β-hexosaminidase A (EC
  • Bacillus subtilis hypothetical protein yzbA.
  • Escherichica coli hypothetical protein ycfO and HI0959, the corresponding Haemophilus influenzae protein.

One of the conserved regions in these enzymes is centered on a conserved aspartic acid residue which has been shown [3], in Aspergillus wentii β-glucosidase A3, to be implicated in the catalytic mechanism. We have used this region as a signature pattern.

Expert(s) to contact by email:

Henrissat B.

Last update:

April 2006 / Pattern revised.


Technical section

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

GLYCOSYL_HYDROL_F3, PS00775; Glycosyl hydrolases family 3 active site  (PATTERN)


1AuthorsHenrissat B.
TitleA classification of glycosyl hydrolases based on amino acid sequence similarities.
SourceBiochem. J. 280:309-316(1991).
PubMed ID1747104

2AuthorsCastle L.A. Smith K.D. Morris R.O.
TitleCloning and sequencing of an Agrobacterium tumefaciens beta-glucosidase gene involved in modifying a vir-inducing plant signal molecule.
SourceJ. Bacteriol. 174:1478-1486(1992).
PubMed ID1537792

3AuthorsBause E. Legler G.
TitleIsolation and structure of a tryptic glycopeptide from the active site of beta-glucosidase A3 from Aspergillus wentii.
SourceBiochim. Biophys. Acta 626:459-465(1980).
PubMed ID6783081

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