三叶肽:从结构到功能

Trefoil peptides: from structure to function

三叶结构域是一段由３８～３９个氨基酸组成的多肽序列，其中包含６个高度保守的半胱氨酸残基，这 ６个半胱氨酸残基以 １－５， ２－４， ３－６的交联方式形成三对二硫键，使多肽链折叠成特征性的三叶结构。已发现的哺乳动物三叶肽有三种：ｐＳ２、ＳＰ及ＩＴＦ。三叶肽通常位于消化道腔面的粘膜层，具有保护和修复功能，在维持粘膜的完整性中发挥着重要作用。

The unique structure in which six cysteine residues in a sequence of 38 or 39 amino acid residues formed three disulfide bonds in a 1-5, 2-4, 3-6 configuration constitutes the basic element of a trefoil domain. The highly conserved amino acid together with the three disulfide bonds forms a distinctive three-trefoil structure. Today three mammalian trefoil factors (pS2, SP and ITF) are known. Trefoil peptides are usually associated with the mucin layer of gastrointestinal tract, protecting and repairing the epithelial layer in the gastrointestinal tract.