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| Expression of the Truncated vip3A Gene at the 3'-terminus from Bacillus thuringiensis in Escherichia coli |
| SHI Yong-xia;XU Wei;YUAN Mei-jin;SUN Fan;PANG Yi |
| State Key Laboratory for Biocontrol, Zhongshan(Sun Yat-sen) University, Guangzhou 510275, China |
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Abstract vip3T gene from Bacillus thuringiensis, which deleted 154 amino-acid encoding sequences at the carbon terminus of Vip3A, was cloned into the expression vector pQE30. The constructed recombinant plasmid pQEvip3T was transformed into Escherichia coli M15 and induced with 1mmol/L IPTG. Protein solubility and insecticidal activity of Vip3T were compared with those of Vip3A. Different from Vip3A, Vip3T existed only in the insoluble inclusion body of induced M15(pQEvip3T). Bioassay showed that M15(pOTP) expressing Vip3A protein performed high toxicity against Spodoptera litura and S. exigua larvae. The purified Vip3A inclusion body lost toxicity against the insects, however, the solubilized inclusion body with Na2CO3 regenerated the insecticidal toxicity. In contrast, the insecticidal activity of induced M15(pQEvip3T), Vip3T inclusion body and its solubilized form against the insect larvae were completely abolished. This suggests that C-terminal amino acids of Vip3A may have an effect on its solubility and insecticidal activity.
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Received: 31 May 2005
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Corresponding Authors:
PANG Yi
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