分子内分子伴侣──Pro肽在蛋白质折叠中的作用

Intramolecular chaperone-the role of Pro peptide in protein folding

在体内，许多蛋白质，如很多胞外蛋白酶、某些多肽激素等都以含前导肽的前体形式合成。前导肽在蛋白质折叠中具有分子伴侣的功能。为了与一般意义上的分子伴侣相区别，人们将对蛋白质折叠有帮助的前导肽称为分子内分子伴侣。分子内分子伴侣帮助蛋白质在折叠过程中克服高的能量障碍，某些蛋白质的分子内分子伴侣甚至促进其在氧化性折叠中二硫键的正确配对。

Many proteins, including most extra-cellular proteases and some hormones , are syn-thesized as precursors with pro regions in vivo. There are increasing evidences that the pro regions have molecular chaperone-like activity on the folding of the proteins they are linked with. To dif-ferentiate from the general molecular chaperones, the term of intramolecular chaperone(IMC)was introduced to refer to this function of Pro peptides. Pro peptides help protein folding transition state overcome large energy barrier in the folding process. The propeptide-assisted protein folding reaction is under kinetic rather than thermodynamic control. Some Pro peptides are shown to enhance the correct disulfide bond formation in oxidative folding process .