Antifreeze, type III (IPR006013)

Short name: Antifreeze_III

Overlapping homologous superfamilies

Family relationships



Marine teleosts from polar oceans can be protected from freezing in icy sea-water by serum antifreeze proteins (AFPs) or glycoproteins (AFGPs) [PMID: 8939756]: these function by binding to, and preventing the growth of, ice crystals within the fish. Despite functional similarity, the proteins are structurally diverse and include glycosylated and at least 3 non-glycosylated forms: the AFGP of nototheniids and cods are polymers of a tripeptide repeat, Ala-Ala-Thr, with a disaccharide attached to the threonine residue; type I AFPs are Ala-rich, alpha-helical peptides found in flounder and sculpin; type II AFPs of sea-raven, smelt and herring are Cys-rich proteins; and type III AFPs, found in eel pouts, are rich in beta-structure [PMID: 8939756]. As well as antifreeze proteins, this domain is also found in the C-terminal region of at least one sialic acid synthase (SAS). The function of this domain in SAS is not known, but it may be involved in sugar binding [PMID: 12171656].

Contributing signatures

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