Protein A, Ig-binding domain (IPR003132)

Short name: Protein_A_Ig-bd

Overlapping homologous superfamilies

Domain relationships



This entry represents the immunoglobulin-binding domain found in the Staphylococcus aureus virulence factor protein A (SpA). Protein A contains five highly homologous Ig-binding domains in tandem (designated domains E, D, A, B and C), which share a common structure consisting of three helices in a closed left-handed twist. 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) [PMID: 10805799].

GO terms

Biological Process

GO:0009405 pathogenesis

Molecular Function

GO:0019865 immunoglobulin binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.