Location of the dipteran specificity region in a lepidopteran-dipteran crystal protein from Bacillus thuringiensis
Location of the dipteran specificity region in a lepidopteran-dipteran crystal protein from Bacillus thuringiensis
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苏云金芽孢杆菌鳞翅目-双翅目晶体蛋白中双翅目特异性区域的位置
DOI：
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发表时间：
1990
影响因子：
3.2
通讯作者：
H. R. Whiteley
中科院分区：
文献类型：
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作者：
W. R. Widner;H. R. Whiteley
苏云金芽孢杆菌苏云金亚种（Bacillus thuringiensis subsp.）kurstaki HD-1，命名为cryIIA和cryIIB（以前分别命名为cryB 1和cryB 2），用于研究宿主范围特异性。它们各自的基因产物有87%相同，但表现出不同的毒性谱; CryIIA对蚊子和烟草天蛾幼虫都有毒，而CryIIB只对后者有毒。产生cryIIA和cryIIB基因的杂交体，并测定其所得基因产物的毒性。对应于残基307至382的CryIIA的短片段被证明足以改变宿主范围特异性-即，当该区域取代CryIIB的相应片段时，所得杂合蛋白获得了对蚊子的毒性。CryIIA和CryIIB多肽在该区域中仅相差18个氨基酸，这表明很少的氨基酸变化可以对这些蛋白质的毒性谱产生实质性影响。
Two highly related crystal protein genes from Bacillus thuringiensis subsp. kurstaki HD-1, designated cryIIA and cryIIB (previously named cryB1 and cryB2, respectively), were used to study host range specificity. Their respective gene products are 87% identical but exhibit different toxicity spectra; CryIIA is toxic to both mosquito and tobacco hornworm larvae, whereas CryIIB is toxic only to the latter. Hybrids of the cryIIA and cryIIB genes were generated, and their resultant gene products were assayed for toxicity. A short segment of CryIIA corresponding to residues 307 through 382 was shown to be sufficient for altering host range specificity-i.e., when this region replaced the corresponding segment of CryIIB, the resulting hybrid protein acquired toxicity against mosquitoes. The CryIIA and CryIIB polypeptides differ by only 18 amino acids in this region, indicating that very few amino acid changes can have a substantial effect on the toxicity spectra of these proteins.