Prokaryotic expression and purification of bombyxin-II in the silkworm( Bombyx mori)

【Aim】To establish a simple,quick and effective method to get a large number of bombyxin-Ⅱ( BBXⅡ). 【Methods】Full-length cDNA of the bombyxin-Ⅱ gene from the silkworm( Bombyx mori) was obtained through RT-PCR technique,and its promoter sequences were cloned based on genome sequences of the silkworm. Meanwhile we got purified BBXⅡ protein by affinity chromatography. 【Results】We obtained the cDNA of bombyxin-Ⅱ by reverse transcription of the mRNA from the head of the silkworm and built the prokaryotic expression vector pET28a-BBXⅡ. The BBXⅡ was highly expressed by IPTG induction. Then we successfully got a large amount of purified BBXⅡ by HisTrap HP affinity chromatography. 【Conclusion】The prokaryotic expression and protein purification technology that we built is a simple and effective method to obtain a lot of preparation of BBXⅡ. The results lay a foundation for further research of the secretion and action mechanisms of BBX and for discovery of BBX hypoglycemic drugs by using prokaryotic expression system.