Summary: Sialidase, N-terminal domain
This is the Wikipedia entry entitled "Glycoside hydrolase family 33". More...
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Glycoside hydrolase family 33 Edit Wikipedia article
|Sialidase, N-terminal domain|
Glycoside hydrolases EC 3.2.1. are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycoside hydrolases, based on sequence similarity, has led to the definition of >100 different families. This classification is available on the CAZy(http://www.cazy.org/GH1.html) web site, and also discussed at CAZypedia, an online encyclopedia of carbohydrate active enzymes.
This family contains sialidases (CAZY GH_33), which hydrolyse alpha-(2->3)-, alpha-(2->6)-, alpha-(2->8)-glycosidic linkages of terminal sialic residues in oligosaccharides, glycoproteins, glycolipids, colominic acid and synthetic substrates. Sialidases may act as pathogenic factors in microbial infections. The 1.8 A structure of trans-sialidase from leech (Macrobdella decora, ) in complex with 2-deoxy-2, 3-didehydro-NeuAc was solved. The refined model comprising residues 81-769 has a catalytic beta-propeller domain, a N-terminal lectin-like domain and an irregular beta-stranded domain inserted into the catalytic domain.
- Henrissat B, Callebaut I, Mornon JP, Fabrega S, Lehn P, Davies G (1995). "Conserved catalytic machinery and the prediction of a common fold for several families of glycosyl hydrolases". Proc. Natl. Acad. Sci. U.S.A. 92 (15): 7090–7094. doi:10.1073/pnas.92.15.7090. PMC 41477. PMID 7624375.
- Henrissat B, Davies G (1995). "Structures and mechanisms of glycosyl hydrolases". Structure 3 (9): 853–859. doi:10.1016/S0969-2126(01)00220-9. PMID 8535779.
- Bairoch, A. "Classification of glycosyl hydrolase families and index of glycosyl hydrolase entries in SWISS-PROT". 1999.
- Henrissat, B. and Coutinho P.M. "Carbohydrate-Active Enzymes server". 1999.
- CAZypedia, an online encyclopedia of carbohydrate-active enzymes.
- Rothe B, Rothe B, Roggentin P, Schauer R (1991). "The sialidase gene from Clostridium septicum: cloning, sequencing, expression in Escherichia coli and identification of conserved sequences in sialidases and other proteins". Mol. Gen. Genet. 226 (1–2): 190–197. doi:10.1007/BF00273603. PMID 2034213.
- Luo M, Luo Y, Li SC, Chou MY, Li YT (1998). "The crystal structure of an intramolecular trans-sialidase with a NeuAc alpha2-->3Gal specificity". Structure 6 (4): 521–530. doi:10.1016/S0969-2126(98)00053-7. PMID 9562562.
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No Pfam abstract.
Internal database links
|Similarity to PfamA using HHSearch:||Laminin_G_3|
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR004124
O-Glycosyl hydrolases (EC) are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycosyl hydrolases, based on sequence similarity, has led to the definition of 85 different families [PUBMED:7624375, PUBMED:8535779]. This classification is available on the CAZy (CArbohydrate-Active EnZymes) web site.
Sialidases (CAZY) hydrolyse alpha-(2->3)-, alpha-(2->6)-, alpha-(2->8)-glycosidic linkages of terminal sialic residues in oligosaccharides, glycoproteins, glycolipids, colominic acid and synthetic substrates. Sialidases may act as pathogenic factors in microbial infections [PUBMED:2034213].
The 1.8 A structure of trans-sialidase from leech (Macrobdella decora, SWISSPROT) in complex with 2-deoxy-2, 3-didehydro-NeuAc was solved. The refined model comprising residues 81-769 has a catalytic beta-propeller domain, a N-terminal lectin-like domain and an irregular beta-stranded domain inserted into the catalytic domain [PUBMED:9562562].
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Molecular function||exo-alpha-sialidase activity (GO:0004308)|
|Biological process||carbohydrate metabolic process (GO:0005975)|
- the number of sequences which exhibit this architecture
a textual description of the architecture, e.g. Gla, EGF x 2, Trypsin.
This example describes an architecture with one
Gladomain, followed by two consecutive
EGFdomains, and finally a single
- the UniProt description of the protein sequence
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This superfamily includes a diverse range of carbohydrate binding domains and glycosyl hydrolase enzymes that share a common structure.
The clan contains the following 16 members:DUF1080 DUF2401 Gal-bind_lectin Glyco_hydro_11 Glyco_hydro_12 Glyco_hydro_16 Glyco_hydro_7 Laminin_G_1 Laminin_G_2 Laminin_G_3 Lectin_leg-like Lectin_legB Pentaxin Sialidase SKN1 Toxin_R_bind_N
We make a range of alignments for each Pfam-A family:
- the curated alignment from which the HMM for the family is built
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Curation and family details
|Seed source:||Structural domain|
|Number in seed:||6|
|Number in full:||557|
|Average length of the domain:||186.90 aa|
|Average identity of full alignment:||45 %|
|Average coverage of the sequence by the domain:||24.36 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||11|
|Download:||download the raw HMM for this family|
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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Sialidase domain has been found. There are 12 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.
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