蛋白质剪接研究进展

Advances in Protein Splicing

蛋白质剪接是一个翻译后自催化加工过程,它不需要酶或其他辅助因子的参与。在这个过程中,前体蛋白的Intein(内含肽)被切离,其两侧的Extein(外显肽)连接在一起。Intein按结构可分为经典Intein和微型Intein,其中的经典Intein包括Hint结构域和中间的归巢内切酶结构域(该结构域在微型内含肽中不存在)。蛋白质剪接及其他具有Hint结构域的蛋白加工过程的起始步骤是N-S/O酰基重排反应,该反应是由Hint结构域催化的;Intein的剪接还分为顺式剪接和反式剪接,通过对Intein进行改造,可以阻断剪接过程,但不影响N端肽键或C端肽键的断裂;通过筛选突变体,可以获得温度敏感型、pH敏感型或小分子诱导型的内含肽。这些研究促进了Intein在多肽制备及其它方面的应用。

Protein splicing is a posttranslational autocatalytic process and is independent of any cofactor or enzyme. During the splicing process the internal protein fragment, intein, triggered the self-excision from the precursor protein and the concomitant ligation of the flanking protein fragments, exteins. Inteins are conventionally divided into two large groups, classical inteins and mini-inteins. A classical intein consists of two domains, Hint domain and a central endonuclease domain. In mini-inteins, the central domain is replaced by a linker sequence which lacks catalytic activity. Protein splicing and the autoprocessing of Hint-containing proteins are initiated by an NO / S shift which is catalyzed by the Hint domain. The protein splicing can also be classified into cis-splicing and trans-splicing. Through modification of intein the splicing can be blocked but the N-or C-terminal cleavage is not changed. Conditionally active intein variants and splicing activators or inhibitors are available by rational screening. These studies have led to the development of novel technologies for polypeptides production and other applications.