| Project/Area Number |
13836008
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Institution | OKAYAMA UNIVERSITY |
|---|
Principal Investigator |
SAKAI Hiroshi Okayama Univ., Fac. Eng., Professor, 工学部, 教授 (60089117)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
YAMAGIWA Masashi Okayama Univ., Fac. Eng., Research Instructor, 工学部, 助手 (00325078)
|
|---|
| Project Period (FY) |
2001 – 2002
|
| Project Status |
Completed (Fiscal Year 2002)
|
| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2002: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2001: ¥2,200,000 (Direct Cost: ¥2,200,000)
|
|---|
| Keywords | Bacillus thruingiensis / Cry11A / specific insecticidal protein / Cry4A / dipteran insect / mosquito |
|---|
| Research Abstract |
The course of processing of the 70-kDa protoxin of Cry11A was analysed. Cry11A is one of the dipteran-specific insecticidal protein produced by Bacillus thuringiensis. Upon tryptic digestion of the 70-kDa protoxin, a 36-kDa fragment and a 32-kDa fragment were produced. Based on the N-terminal amino acid sequences of the fragments, it was strongly suggested that the two fragments were produced by intramolecular cleavage of the 70-kDa protoxin. By engineering the cry11A gene, the genes encoding fusion proteins GST11A-36k and GST11A-32k were constructed, in which the GST tract was attached onto the N-termini of the 36-kDa and the 32-kDa fragments, respectively. Another fusion protein 32k-His was constructed, in which a histidine hexamer was attached onto the C-terminus of the 32-kDa fragment. Neither GST11A-36k nor GST11lA-32k was insecticidal toward the mosquito larvae. The two fragments proved to associate to form a heterodimer. Because the complex consisting of the 36-kDa and the 32-kDa fragments exhibited the significant insecticidal activity toward the mosquito larvae, it was suggested that the complex was one of the active forms of Cry11A. Moreover, we have found Cry11A-specific binding proteins in the brush border membrane vesicle from the mosquito larvae. It was also suggested that the Cry 11A-specific binding site on the target cell membrane is separate from the Cry4A-specific one. Thus, it was strongly suggested that the insecticidal mechanism of Cry11A is novel one different from that of Cry4A, a representative dipteran-specific insecticidal protein of B.thuringiensis.10.
|
