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Bacterial immunoglobulin/albumin-binding domains superfamily

SCOP classification
Root:   SCOP hierarchy in SUPERFAMILY [ 0] (11)
Class:   All alpha proteins [ 46456] (284)
Fold:   immunoglobulin/albumin-binding domain-like [ 46996] (11)
Superfamily:   Bacterial immunoglobulin/albumin-binding domains [ 46997] (2)
Families:   Immunoglobulin-binding protein A modules [ 46998]
  GA module, an albumin-binding domain [ 47001] (3)

Superfamily statistics
Genomes (145) Uniprot 2018_03 genome PDB chains (SCOP 1.75)
Domains 4,951 17,621 16
Proteins 278 1,852 15

Functional annotation
General category Other
Detailed category Viral proteins

Function annotation of SCOP domain superfamilies

InterPro annotation
Cross references IPR009063 SSF46997 Protein matches

This entry represents immunoglobulin and albumin-binding (GA module) domains from various bacterial proteins, which share a common fold consisting of a left-handed three-helical bundle (mirror topology to spectrin-like fold).

The Staphylococcus aureus virulence factor protein A (SpA) contains five highly homologous Ig-binding domains in tandem (designated domains E, D, A, B and C) that share this common structure. Protein A can exist in both secreted and membrane-bound forms, and has two distinct Ig-binding activities: each domain can bind Fc-gamma (the constant region of IgG involved in effector functions) and Fab (the Ig fragment responsible for antigen recognition) [PubMed10805799].

Protein G-related albumin-binding (GA) modules occur on the surface of numerous Gram-positive bacterial pathogens. Protein G of group C and G Streptococci interacts with the constant region of IgG and with human serum albumin. The GA module is found in a range of bacterial cell surface proteins [PubMed15269208, PubMed9086265]. GA modules may promote bacterial growth and virulence in mammalian hosts by scavenging albumin-bound nutrients and camouflaging the bacteria. Variations in sequence give rise to differences in structure and function between GA modules in different proteins, which could alter pathogenesis and host specificity due to their varied affinities for different species of albumin [PubMed16906768]. Proteins containing a GA module include PAB from Peptostreptococcus magnus [PubMed7589548].

InterPro database

PDBeMotif information about ligands, sequence and structure motifs
Cross references PDB entries
Ligand binding statistics
Nucleic-acid binding statistics
Occurrence of secondary structure elements
Occurrence of small 3D structural motifs

PDBeMotif resource

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Internal database links

Browse genome assignments for this superfamily. The SUPERFAMILY hidden Markov model library has been used to carry out SCOP domain assignments to all genomes at the superfamily level.

Alignments of sequences to 21 models in this superfamily are available by clicking on the 'Alignments' icon above. PDB sequences less than 40% identical are shown by default, but any other sequence(s) may be aligned. Select PDB sequences, genome sequences, or paste in or upload your own sequences.

Browse and view proteins in genomes which have different domain combinations including a Bacterial immunoglobulin/albumin-binding domains domain.

Examine the distribution of domain superfamilies, or families, across the major taxonomic kingdoms or genomes within a kingdom. This gives an immediate impression of how superfamilies, or families, are restricted to certain kingdoms of life.

Explore domain occurrence network where nodes represent genomes and edges are domain architectures (shared between genomes) containing the superfamily of interest.

There are 21 hidden Markov models representing the Bacterial immunoglobulin/albumin-binding domains superfamily. Information on how the models are built, and plots showing hydrophobicity, match emmission probabilities and insertion/deletion probabilities can be inspected.

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