信号肽序列及其在蛋白质表达中的应用

信号肽在蛋白分泌的过程中起重要作用，分泌性蛋白质合成后由信号肽引导其穿过合成所在的细胞到其他组织细胞中。可以利用因特网在线工具和信号序列捕获系统来判定基因序列中是否含有信号肽序列。外源蛋白的表达形式多为细胞内不溶性表达(包涵体)，少数为细胞外分泌表达。利用信号肽来引导外源蛋白分泌可避免因包涵体复性带来的困难。研究表明，多种外源基因连接上信号肽后在原核表达系统如大肠杆菌、L型细菌、芽孢杆菌和乳酸杆菌中等都得到了分泌表达；信号肽也广泛应用于真核表达系统如毕赤酵母和昆虫杆状病毒表达系统，以提高蛋白的表达量。

Signal Peptide Sequence and its Application to Protein Expression

Secretory proteins, which had been synthesized in cell, were transferred to other tissues and cells. Signal peptides played important roles in this process. Internet tools and signal sequence trap could discern the signal sequences. Only a few foreign proteins were secreted to the extracellular fluid, others were expressed as inclusion bodies in cells. In order to avoid the renaturation process of protein, signal sequences were employed to direct protein secretion. Numbers of heterologous genes, which added to signal sequence, could be expressed as secretory proteins in the prokaryote expression system such as E.coli, L-form bacteria, Bacillus and Lactobacillus casei. Signal peptides were applied widely to improve the yield of protein expression in the eukaryote expression system such as Pichia pastoris and insect cell.