Comparison of the expression of Bacillus thuringiensis full-length and N-terminally truncated vip3A gene in Escherichia coli.
OBJECTIVE
Studies were performed to demonstrate the function of the putative signal peptide of Vip3A proteins in Escherichia coli.


RESULTS
The full-length vip3A-S184 gene was isolated from a soil-isolated Bacillus thuringiensis, and the vip3AdeltaN was constructed by deleting 81 nucleotides at the 5'-terminus of vip3A-S184. Both were transformed and expressed in E. coli. About 19.2% of Vip3A-S184 proteins secreted soluble proteins and others formed inclusion bodies in the periplasmic space. In contrast, the Vip3AdeltaN was insoluble and formed inclusion bodies in the cytoplasm. Bioassay indicated that Vip3A-S184 showed different toxicity against Spodoptera exigua, Helicoverpa armigera and S. litura, but Vip3AdeltaN showed no toxicity to either of them because of the deletion of the first 27 amino acids at the N-terminus.


CONCLUSIONS
The results suggest that the deleted N-terminal sequences were essential for the secretion of Vip3A-S184 protein in E. coli and might be required for toxicity.


CONCLUSIONS
The function of the putative signal peptide of Vip3A protein in E. coli was investigated. These would be helpful to make clear the unknown secretion pathway of Vip3A protein in B. thuringiensis and determine the receptor-binding domain or toxic fragment of Vip3A-S184 protein.
Chen
J
J
State Key Laboratory for Biocontrol & Institute of Entomology, Zhongshan University, Guangzhou, China.
Yu
J
J
Tang
L
L
Tang
M
M
Shi
Y
Y
Pang
Y
Y
D000595:Amino Acid Sequence; D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism / Q000633:toxicity; D001681:Biological Assay / Q000379:methods; D015153:Blotting, Western; D002458:Cell Fractionation; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism*; D015870:Gene Expression; D005822:Genetic Vectors; D002479:Inclusion Bodies / Q000737:chemistry; D007915:Lepidoptera / Q000187:drug effects; D021382:Protein Sorting Signals / Q000502:physiology; D018411:Spodoptera / Q000187:drug effects; D013329:Structure-Activity Relationship
D001426:Bacterial Proteins; D021382:Protein Sorting Signals; C447139:Vip3A protein, Bacillus thuringiensis