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68  structures 746  species 0  interactions 1180  sequences 76  architectures

Family: BNR (PF02012)

Summary: BNR/Asp-box repeat

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This is the Wikipedia entry entitled "Bacterial neuraminidase". More...

Bacterial neuraminidase Edit Wikipedia article

BNR/Asp-box repeat
PDB 1euu EBI.jpg
Structure of a bacterial sialidase.[1]
Pfam clanCL0434

Bacterial neuraminidase is type of neuraminidase and a virulence factor for many bacteria including Bacteroides fragilis and Pseudomonas aeruginosa. Its function is to cleave a sialic acid residue off ganglioside-GM1 (a modulator of cell surface and receptor activity) turning it into asialo-GM1 to which type 4 pilli (attachment factors) bind preferentially.


  1. ^ Gaskell A, Crennell S, Taylor G (November 1995). "The three domains of a bacterial sialidase: a beta-propeller, an immunoglobulin module and a galactose-binding jelly-roll". Structure. 3 (11): 1197–205. doi:10.1016/s0969-2126(01)00255-6. PMID 8591030.

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

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.

BNR/Asp-box repeat Provide feedback

Members of this family contain multiple BNR (bacterial neuraminidase repeat) repeats or Asp-boxes. The repeats are short, however the repeats are never found closer than 40 residues together suggesting that the repeat is structurally longer. These repeats are found in many glycosyl hydrolases as well as other extracellular proteins of unknown function.

Literature references

  1. Roggentin P, Rothe B, Kaper JB, Galen J, Lawrisuk L, Vimr ER, Schauer R; , Glycoconj J 1989;6:349-353.: Conserved sequences in bacterial and viral sialidases. PUBMED:2562507 EPMC:2562507

  2. Copley RR, Russell RB, Ponting CP; , Protein Sci 2001;10:285-292.: Sialidase-like Asp-boxes: sequence-similar structures within different protein folds. PUBMED:11266614 EPMC:11266614

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR002860

Members of this entry contain multiple BNR (bacterial neuraminidase repeat) repeats or Asp-boxes. The repeats are short, however the repeats are never found closer than 40 residues together suggesting that the repeat is structurally longer. These repeats are found in a variety of non-homologous proteins, including bacterial ribonucleases, sulphite oxidases, reelin, netrins, sialidases, neuraminidases, some lipoprotein receptors, and a variety of glycosyl hydrolases [ PUBMED:11266614 ].

Domain organisation

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

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Pfam Clan

This family is a member of clan Sialidase (CL0434), which has the following description:

This superfamily includes sialidases enzymes. Several viruses use sialic acid as a cell surface receptor for host invasion. These viruses then have cell surface neuraminidase enzymes to cleave sialic acid from cell surface proteins allowing them to leave the host cell after replication. This superfamily are composed of six beta-sheets that form a six-fold beta-propeller structure. Many members of this superfamily contain BNR sequence motifs Pfam:PF02012.

The clan contains the following 16 members:

BNR BNR_2 BNR_3 BNR_4 BNR_6 End_beta_barrel End_beta_propel Fungal_lectin HN Mcl1_mid Neur Neuraminidase OLF Phytase PSII_BNR Sortilin-Vps10


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

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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.

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Curation and family details

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Seed source: Bateman A
Previous IDs: none
Type: Repeat
Sequence Ontology: SO:0001068
Author: Bateman A
Number in seed: 96
Number in full: 1180
Average length of the domain: 12.00 aa
Average identity of full alignment: 51 %
Average coverage of the sequence by the domain: 2.87 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 57096847 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 27.0 12.4
Trusted cut-off 27.0 12.4
Noise cut-off 26.9 12.3
Model length: 12
Family (HMM) version: 22
Download: download the raw HMM for this family

Species distribution

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Colour assignments

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


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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 BNR domain has been found. There are 68 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
P32319 View 3D Structure Click here