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521  structures 4155  species 0  interactions 29293  sequences 945  architectures

Family: Glyco_hydro_18 (PF00704)

Summary: Glycosyl hydrolases family 18

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

This is the Wikipedia entry entitled "Glycoside hydrolase family 18". More...

Glycoside hydrolase family 18 Edit Wikipedia article

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This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Glycosyl hydrolases family 18 Provide feedback

No Pfam abstract.

Literature references

  1. Perrakis A, Tews I, Dauter Z, Oppenheim AB, Chet I, Wilson KS, Vorgias CE; , Structure 1994;2:1169-1180.: Crystal structure of a bacterial chitinase at 2.3 A resolution. PUBMED:7704527 EPMC:7704527


Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR001223

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) website.

The glycosyl hydrolases family 18 (GH18) CAZY is widely distributed in all kingdoms and contains hydrolytic enzymes with chitinase or endo-N-acetyl-beta-D-glucosaminidase (ENGase) activity as well as chitinase-like lectins (chi-lectins/proteins (CLPs). Chitinases ( EC ) are hydrolytic enzymes that cleave the beta-1,4-bond releasing oligomeric, dimeric (chitobiose) or monomeric (N-actetylglucosamine, GlcNAc) products. ENGases ( EC ) hydrolyze the beta-1,4 linkage in the chitobiose core of N-linked glycans from glycoproteins leaving one GlcNAc residue on the substrate. CLPs do not display chitinase activity but some of them have been reported to have specific functions and carbohydrate binding property [ PUBMED:22550243 ]. This family also includes glycoproteins from mammals, such as oviduct-specific glycoproteins.

The catalytic domain of GH18s has a common (beta/alpha)8 triosephosphate isomerase (TIM)-barrel structure, which consists of a barrel-like framework made from eight internal parallel beta-strands that are alternately connected by eight exterior alpha-helices. The active site motif DxxDxDxE is essential for the activity of the GH18 catalytic domain. [ PUBMED:22742450 , PUBMED:22859955 , PUBMED:24380021 ].

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Domain organisation

Below is a listing of the unique domain organisations or architectures in which this domain is found. More...

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Alignments

We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets and the UniProtKB sequence database. More...

View options

We make a range of alignments for each Pfam-A family. You can see a description of each above. You can view these alignments in various ways but please note that some types of alignment are never generated while others may not be available for all families, most commonly because the alignments are too large to handle.

  Seed
(159)
Full
(29293)
Representative proteomes UniProt
(75474)
RP15
(4557)
RP35
(13379)
RP55
(25012)
RP75
(37745)
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HTML View             
PP/heatmap 1            

1Cannot generate PP/Heatmap alignments for seeds; no PP data available

Key: ✓ available, x not generated, not available.

Format an alignment

  Seed
(159)
Full
(29293)
Representative proteomes UniProt
(75474)
RP15
(4557)
RP35
(13379)
RP55
(25012)
RP75
(37745)
Alignment:
Format:
Order:
Sequence:
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Download options

We make all of our alignments available in Stockholm format. You can download them here as raw, plain text files or as gzip-compressed files.

  Seed
(159)
Full
(29293)
Representative proteomes UniProt
(75474)
RP15
(4557)
RP35
(13379)
RP55
(25012)
RP75
(37745)
Raw Stockholm Download   Download   Download   Download   Download   Download   Download  
Gzipped Download   Download   Download   Download   Download   Download   Download  

You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

HMM logo

HMM logos is one way of visualising profile HMMs. Logos provide a quick overview of the properties of an HMM in a graphical form. You can see a more detailed description of HMM logos and find out how you can interpret them here. More...

Trees

This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

Note: You can also download the data file for the tree.

Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation View help on the curation process

Seed source: Pfam-B_574 (release 2.1)
Previous IDs: glycosyl_hydro8;
Type: Domain
Sequence Ontology: SO:0000417
Author: Bateman A
Number in seed: 159
Number in full: 29293
Average length of the domain: 301.10 aa
Average identity of full alignment: 17 %
Average coverage of the sequence by the domain: 57.36 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null --hand HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 29.6 29.6
Trusted cut-off 29.6 29.6
Noise cut-off 29.5 29.5
Model length: 312
Family (HMM) version: 31
Download: download the raw HMM for this family

Species distribution

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Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence

Selections

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This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the adjacent tab. More...

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Structures

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 Glyco_hydro_18 domain has been found. There are 521 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 sequence.

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AlphaFold Structure Predictions

The list of proteins below match this family and have AlphaFold predicted structures. Click on the protein accession to view the predicted structure.

Protein Predicted structure External Information
A0A0G2JDS2 View 3D Structure Click here
A0A0K3AUR1 View 3D Structure Click here
A0A0N7KTE2 View 3D Structure Click here
A0A0P0W9B7 View 3D Structure Click here
A0A0P0XHR1 View 3D Structure Click here
A0A0R0EHM4 View 3D Structure Click here
A0A0R0ETF9 View 3D Structure Click here
A0A0R0FAL2 View 3D Structure Click here
A0A0R0GP25 View 3D Structure Click here
A0A0R0IHC8 View 3D Structure Click here
A0A0R0JAV1 View 3D Structure Click here
A0A0R4IEY0 View 3D Structure Click here
A0A0R4IJ02 View 3D Structure Click here
A0A1D6HG33 View 3D Structure Click here
A0A1D6HTN8 View 3D Structure Click here
A0A1D6HTN9 View 3D Structure Click here
A0A1D6HXA8 View 3D Structure Click here
A0A1D6HXA9 View 3D Structure Click here
A0A1D6HXB0 View 3D Structure Click here
A0A1D6KV11 View 3D Structure Click here
A0A1D6KV12 View 3D Structure Click here
A0A1D6LZN2 View 3D Structure Click here
A0A1D6MEM1 View 3D Structure Click here
A0A1D6MW10 View 3D Structure Click here
A0A1D6N6L9 View 3D Structure Click here
A0A1D6N6M0 View 3D Structure Click here
A0A1D6N6M1 View 3D Structure Click here
A0A1D6N6M2 View 3D Structure Click here
A0A1D6PXG5 View 3D Structure Click here
A0A286YA73 View 3D Structure Click here
A0JPQ9 View 3D Structure Click here
A0S5V8 View 3D Structure Click here
A4HWX6 View 3D Structure Click here
B4F8H2 View 3D Structure Click here
B4F9H4 View 3D Structure Click here
B4FBN8 View 3D Structure Click here
B4FR99 View 3D Structure Click here
B4G1T3 View 3D Structure Click here
B7F946 View 3D Structure Click here
C6T8G2 View 3D Structure Click here