P-type trefoil domain superfamily
IPR044913
Definition
A cysteine-rich domain of approximately forty five amino-acid residues has been found in some extracellular eukaryotic proteins [[cite:PMID:7820556], [cite:PMID:9187350], [cite:PMID:8518738], [cite:PMID:8267796]]. It is known as either the 'P', 'trefoil' or 'TFF' domain, and contains six cysteines linked by three disulphide bonds with connectivity 1-5, 2-4, 3-6. This leads to a characteristic three leafed structure ('trefoil'). The P-type domain is clearly composed of three looplike regions. The central core of the domain consists of a short two-stranded antiparallel β-sheet, which is capped by an irregular loop and forms a central hairpin (loop 3). The β-sheet is preceded by a short α-helix, with majority of the remainder of the domain contained in two loops, which lie on either side of the central hairpin. This domain has been found in a variety of extracellular eukaryotic proteins [[cite:PMID:7820556], [cite:PMID:8518738], [cite:PMID:8267796]], including: Protein pS2 (TFF1), a protein secreted by the stomach mucosa Spasmolytic polypeptide (SP) (TFF2), a protein of about 115 residues that inhibits gastrointestinal motility and gastric acid secretion Intestinal trefoil factor (ITF) (TFF3) Xenopus laevis stomach proteins xP1 and xP4 Xenopus integumentary mucins A.1 (FIM-A.1 or preprospasmolysin) and C.1 (FIM-C.1), proteins which may be involved in defence against microbial infections by protecting the epithelia from the external environment Xenopus skin protein xp2 (or APEG) Zona pellucida sperm-binding protein B (ZP-B) Intestinal sucrase-isomaltase ([ec:3.2.1.48] / [ec:3.2.1.10]), a vertebrate membrane bound, multifunctional enzyme complex which hydrolyses sucrose, maltose and isomaltose Lysosomal alpha-glucosidase ([ec:3.2.1.20])
10 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
Loading the interactive Seroatlas explorer...