| 摘要: |
| 本实验构建了免疫毒素DAB389(Gly4Ser)2-aMSH的两种表达质粒，其一为胞内表达质粒pET28a/DAB389(Gly4Ser)2-aMSH，其二为胞周质表达质粒pET20b /DAB389(Gly4Ser)2-aMSH，实验结果显示，置于胞质表达质粒的DAB389(Gly4Ser)2-aMSH在大肠杆菌的周质腔内分泌表达，而置于胞周质表达质粒的DAB389(Gly4Ser)2-aMSH却不能表达。通过分析免疫毒素的特性，发现DAB389(Gly4Ser)2-aMSH中并不存在信号肽序列；通过与革兰氏阴性细菌中已发现的四种蛋白质分泌途径特性相比较，我们发现它不属于其中的任何一种，可能为一种新型细菌分泌机制，故特将此种现象提出供学者们思考。 |
| 关键词: 分泌机制，信号肽，DAB389(Gly4Ser)2-aMSH |
| DOI： |
| 投稿时间：2010-11-20修订日期：2010-12-30 |
| 基金项目: |
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| A possible secretion system of E.coli |
| lizehong |
| (College of life science, JiLin Agriculture University) |
| Abstract: |
| Prokaryotic cytoplasmic and periplasmic expression vectors (pET28a/DAB389(Gly4Ser)2-aMSH and pET/20b-DAB389(Gly4Ser)2-aMSH)were constructed to study the expression of immunotoxin DAB389(Gly4Ser)2-aMSH in E.coli repectively. Experimental results indicate DAB389(Gly4Ser)2-aMSH was directed to periplasmic space a of Rosettablue(DE3) with vector pET28a/DAB389(Gly4Ser)2-aMSH,on the other hand, DAB389(Gly4Ser)2-aMSH wasn’t expressed in Rosettablue(DE3) with vector pET20b/ -DAB389(Gly4Ser)2-aMSH.Western-blotting showed that the expressed protein could react with the specific horse sera against diphtheria toxin. Through analysising the characteristic of DAB389(Gly4Ser)2-aMSH with SignalP 3.0 Server（Technical University of Denmark）,the results were showed DAB389(Gly4Ser)2-aMSH didn’t include signal peptide.Compared with regularity of expression of secretion systems of Gram-negative bacteria ,this expression of secretion system didn’t belong to any of the above mechanisms.Therefore, we put forward the following idea:there may be another new expression of secretion system in E.coli. |
| Key words: secretion system signal peptide DAB389(Gly4Ser)2-aMSH |
