SUPERFAMILY 1.73 HMM library and genome assignments server


Sialidases superfamily

SCOP classification
Root:   SCOP hierarchy in SUPERFAMILY [ 0] (11)
Class:   All beta proteins [ 48724] (165)
Fold:   6-bladed beta-propeller [ 50938] (11)
  consists of six 4-stranded beta-sheet motifs; meander
Superfamily:   Sialidases [ 50939] (2)
Families:   Sialidases (neuraminidases) [ 50940] (9)
  Endo-alpha-sialidase [ 117276]
  possibly related by the other family by circular permutation; includes extra N-terminal domain [dN: alpha/beta ] and insert domain [dI: beta-barrel, similar to the Reductase/isomerase/elongation factor common domain (scop_cf 50412)]


InterPro annotation
Cross references IPR011040 SSF50939 Protein matches
Abstract

Neuraminidases (sialidases) hydrolyse the non-reducing, terminal sialic acid linkage in various natural substrates, such as glycoproteins, glycolipids, gangliosides, and polysaccharides [PubMed12374200]. In mammals, neuraminidases occur in the lysosome, the cytosol, and associated with the plasma membrane. Neuraminidases have also been implicated in the pathogenesis of many diseases. For example, in viruses neuraminidases enable the transport of the virus through mucin, the eruption of the virus from the infected host cell, and the prevention of self-aggregation of virus particles through the destruction of the host cell receptor recognised by the virus [PubMed14561719]. Eukaryotic, bacterial and viral neuraminidases share highly conserved regions of beta-sheet motifs. Bacterial neuraminidases often possess domains in addition to the catalytic neuraminidase domain, for instance the neuraminidase from Micromonospora viridifaciens contains three domains, of which the catalytic domain described here is the N-terminal domain [PubMed8591030]. Similarly, leech neuraminidase is a multidomain protein, where the catalytic domain is the C-terminal domain [PubMed9878409]. In several paramyxoviruses, neuraminidase forms part of the multi-functional haemagglutinin-neuraminidase glycoprotein found on the viral envelope [PubMed14729348].


InterPro database

Functional annotation
General category Metabolism
Detailed category Polysaccharide metabolism and transport

Function annotation of SCOP domain superfamilies

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Internal database links

The SUPERFAMILY hidden Markov model library has been used to carry out SCOP domain assignments to all genomes at the superfamily level. Click on the 'Genome Assignments' icon above to view the genome assignments for this superfamily.


Alignments of sequences to

Alignments of sequences to 14 models in this superfamily are available by clicking on the superfamily level 'Alignments' icon above. PDB sequences less than 40% identical are shown by default, but any other sequences may be aligned. Select PDB sequences, genome sequences, or paste in or upload your own.


It is possible to browse and view the proteins in the genomes which have different combinations of domains including a Sialidases domain. Click on the 'Domain Combinations' icon.


To view the distribution of domain superfamilies, or families, across the major taxonomic kingdoms or genomes within a kingdom click on the 'TaxViz' icon above. This gives an immediate impression of how superfamilies, or families, are restricted to certain kingdoms of life.


Undirected domain occurrence networks are available for all superfamilies. Nodes in these networks represent genomes. Connections between nodes represent the presence of domain architectures, which contain the superfamily of interest, in both genomes.

There are 14 hidden Markov models representing the Sialidases superfamily. Information on how the models are built, and plots showing hydrophobicity, match emmission probabilities and insertion/deletion probabilities can be viewed by clicking on the icon above.


Jump to [ Top of page · SCOP classification · InterPro annotation · Functional annotation · Internal database links ]