Immunoglobulin domain
Structure of an antigen binding fragment of an antibody.
Identifiers
Symbol	ig
Pfam	PF00047
Pfam clan	CL0159
InterPro	IPR013151
PROSITE	PDOC00262
SCOP2	8fab / SCOPe / SUPFAM
OPM superfamily	193
OPM protein	5f71
CDD	cd00096
Membranome	2
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

The immunoglobulin domain, also known as the immunoglobulin fold, is a type of protein domain that consists of a 2-layer sandwich of 7-9 antiparallel β-strands arranged in two β-sheets with a Greek key topology, ^{[1] [2]} consisting of about 125 amino acids.

The backbone switches repeatedly between the two β-sheets. Typically, the pattern is (N-terminal β-hairpin in sheet 1)-(β-hairpin in sheet 2)-(β-strand in sheet 1)-(C-terminal β-hairpin in sheet 2). The cross-overs between sheets form an "X", so that the N- and C-terminal hairpins are facing each other.

Members of the immunoglobulin superfamily are found in hundreds of proteins of different functions. Examples include antibodies, the giant muscle kinase titin, and receptor tyrosine kinases. Immunoglobulin-like domains may be involved in protein–protein and protein– ligand interactions. ^[3]

Examples

Human genes encoding proteins containing the immunoglobulin domain include:

See also

• Immunoglobulin superfamily

References

External links

• SCOP listing of immunoglobulin domains of known structure