分子伴侣过量表达对蛋白质分泌及可溶性的影响

 通过过量表达大肠杆菌分子伴侣 Sec B和 Gro EL,研究了它们对靶蛋白的分泌及可溶性的影响 .在过量表达 Sec B的宿主菌中 ,周质空间分泌蛋白总量较对照组提高了约 71 % ,GL- 7- ACA酰化酶在周质空间酶的活力较对照组提高了约 1 .5倍 ,碱性磷酸酯酶在周质空间酶的活力较对照组提高了约 54% ;在过量表达 Gro EL的宿主菌中 ,周质分泌蛋白总量较对照组提高了约 52 % ,青霉素 G酰化酶在周质空间酶的活力较对照组提高了约 76% ,鲑鱼降钙素六聚体的可溶性组分的比例由原来的 45%增加到约 90 % ,而 MS2 -人白介素 - 3融合蛋白的包涵体有约 1 5%转变为可溶性组份 .上述结果表明 ,分子伴侣 Sec B和 Gro EL的过量表达促进了靶蛋白的分泌 ,Gro EL增加了靶蛋白的可溶性

The Effect of Over-expression of Chaperones on the Secretion and the Solubility of Proteins*

The effect of over expression of chaperones SecB and GroEL on the secretion and solubility of protein in Escherichia coli was examined,using a set of the proteins.A diverse range of effects on protein solubility and secretion was observed,and these effects were highly dependent on the particular chaperone.In the host strain over expressing chaperone SecB harboring pSecB,the amount of total periplasmic proteins was increased by about 71% and the activities of alkaline phosphatase(AP) and GL 7 ACA acylase(GL7A) were increased by about 54% and 1.5 fold respectively.In the host strain over expressing chaperone GroEL bearing pGroEL,the amount of total periplasmic proteins was increased by 52%,and the activity of penicillin G acylase(PA)was increased by about 76%;about 90% of Hexameric Calcitonin(Cal6)inclusion body and 15% of MS2 interleukin3(MS2 HIL3)inclusion body became soluble respectively.All the data were compared with the parental strains un bearing plasmids pSecB or pGroEL.In conclusion,the over expression of chaperones SecB and GroEL enhanced the secretion of the proteins,and GroEL also increased the solubility of recombinant proteins.