Baculoviral polyhedrin-Bacillus thuringiensis toxin fusion protein: a protein-based bio-insecticide expressed in Escherichia coli.
Previously, we found that baculoviral polyhedrin (Polh) used as a fusion partner for recombinant expression in Escherichia coli showed almost the same characteristics (rapid solubilization under alkaline conditions and specific degradation by specific alkaline proteases in insect midgut) as the native baculoviral Polh, and formed easily isolatable inclusion bodies. Here, Polh derived from the Autographa californica nuclear polyhedrosis virus (AcNPV) was fused with a Bacillus thuringiensis (Bt) toxin protein (truncated Cry1Ac having toxin region as a model Bt toxin) for the novel generation of a new bio-insecticide. The Polh-Cry1Ac fusion protein (approximately 99 kDa) was highly expressed (3.6-fold induction as compared to E. coli-derived single Cry1Ac (approximately 68 kDa)) as an insoluble inclusion body fraction in E. coli. Trypsin and alpha-chymotrypsin, which have similar properties to the insect midgut alkaline proteases, rapidly degraded the Polh portion in vitro, leaving only the toxic Cry1Ac protein behind. In vivo, the Polh-Cry1Ac fusion protein showed high insecticidal activity against the pest, Plutella xylostella. Because this novel bio-insecticide employs E. coli as the host, mass production at a low cost should be possible. Also, since this is a protein-based insecticide, living modified organism (LMO) issues such as environmental and ecological safety can be avoided.
Department of Chemical Engineering & Division of Molecular and Life Sciences, Pohang University of Science and Technology, Pohang, Korea.
Jeong Hyun
JH
Seo
Joo Sang
JS
Yeo
Hyung Joon
HJ
Cha
D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D001427:Bacterial Toxins / Q000235:genetics* / Q000378:metabolism*; D016367:Baculoviridae / Q000235:genetics / Q000378:metabolism*; D004731:Endotoxins / Q000235:genetics* / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D006460:Hemolysin Proteins; D007306:Insecticides / Q000378:metabolism*; D009036:Moths; D010572:Pest Control, Biological / Q000379:methods*; D015202:Protein Engineering / Q000379:methods; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection / Q000379:methods; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis