 |
|
| PROSITE documentation PDOC00495 [for PROSITE entry PS00572] |
Glycosyl hydrolases family 1 signatures
It has been shown [1,2,3,4] that the following glycosyl hydrolases can be, on the basis of sequence similarities, classified into a single family:
- β-glucosidases (EC 3.2.1.21) from various bacteria such as Agrobacterium strain ATCC 21400, Bacillus polymyxa, and Caldocellum saccharolyticum.
- Two plants (clover) β-glucosidases (EC 3.2.1.21).
- Two different β-galactosidases (EC 3.2.1.23) from the archaebacteria Sulfolobus solfataricus (genes bgaS and lacS).
- 6-phospho-β-galactosidases (EC 3.2.1.85) from various bacteria such as Lactobacillus casei, Lactococcus lactis, and Staphylococcus aureus.
- 6-phospho-β-glucosidases (EC 3.2.1.86) from Escherichia coli (genes bglB and ascB) and from Erwinia chrysanthemi (gene arbB).
- Plants myrosinases (EC 3.2.1.147) (sinigrinase) (thioglucosidase).
- Mammalian lactase-phlorizin hydrolase (LPH) (EC 3.2.1.108 / EC 3.2.1.62). LPH, an integral membrane glycoprotein, is the enzyme that splits lactose in the small intestine. LPH is a large protein of about 1900 residues which contains four tandem repeats of a domain of about 450 residues which is evolutionary related to the above glycosyl hydrolases.
One of the conserved regions in these enzymes is centered on a conserved glutamic acid residue which has been shown [5], in the β-glucosidase from Agrobacterium, to be directly involved in glycosidic bond cleavage by acting as a nucleophile. We have used this region as a signature pattern. As a second signature pattern we selected a conserved region, found in the N-terminal extremity of these enzymes, this region also contains a glutamic acid residue.
Note:This pattern will pick up the last two domains of LPH; the first two domains, which are removed from the LPH precursor by proteolytic processing, have lost the active site glutamate and may therefore be inactive [4].
Consensus pattern:F-x-[FYWM]-[GSTA]-x-[GSTA]-x-[GSTA](2)-[FYNH]-[NQ]-x-E-x- [GSTA]
Sequences known to belong to this class detected by the pattern:ALL.
Other sequence(s) detected in Swiss-Prot:NONE.
Note:This pattern will pick up the last three domains of LPH.
Expert(s) to contact by email: Last update:November 1995 / Patterns and text revised.
PROSITE methods (with tools and information) covered by this documentation:
| 1 | Authors | Henrissat B. |
| Title | A classification of glycosyl hydrolases based on amino acid sequence similarities. | |
| Source | Biochem. J. 280:309-316(1991). | |
| PubMed ID | 1747104 |
| 2 | Authors | Henrissat B. |
| Title | Sequence homology between a beta-galactosidase and some beta-glucosidases. | |
| Source | Protein Seq. Data Anal. 4:61-62(1991). | |
| PubMed ID | 1924272 |
| 3 | Authors | Gonzalez-Candelas L., Ramon D., Polaina J. |
| Source | Gene 95:31-38(1990). |
| 4 | Authors | El Hassouni M., Henrissat B., Chippaux M., Barras F. |
| Source | J. Bacteriol. 174:765-777(1992). |
| 5 | Authors | Withers S.G., Warren R.A.J., Street I.P., Rupitz K., Kempton J.B., Aebersold R. |
| Source | J. Am. Chem. Soc. 112:5887-5889(1990). |
PROSITE is copyright. It is produced by the SIB Swiss Institute Bioinformatics. There are no restrictions on its use by non-profit institutions as long as its content is in no way modified. Usage by and for commercial entities requires a license agreement. For information about the licensing scheme send an email to Prosite License or see: prosite_license.html.
View entry in original PROSITE document format
View entry in raw text format (no links)