Xia Li-Qiu, Zhao Xin-Min, Ding Xue-Zhi, Wang Fa-Xiang, Sun Yun-Jun
Key Laboratory for Microbial Molecular Biology of Hunan Province, College of Life Science, Hunan Normal University, Changsha 410081, China.
J Mol Model. 2008 Sep;14(9):843-8. doi: 10.1007/s00894-008-0318-8. Epub 2008 May 27.
Cry5Ba is a delta-endotoxin produced by Bacillus thuringiensis PS86A1 NRRL B-18900. It is active against nematodes and has great potential for nematode control. Here, we predict the first theoretical model of the three-dimensional (3D) structure of a Cry5Ba toxin by homology modeling on the structure of the Cry1Aa toxin, which is specific to Lepidopteran insects. Cry5Ba resembles the previously reported Cry1Aa toxin structure in that they share a common 3D structure with three domains, but there are some distinctions, with the main differences being located in the loops of domain I. Cry5Ba exhibits a changeable extending conformation structure, and this special structure may also be involved in pore-forming and specificity determination. A fuller understanding of the 3D structure will be helpful in the design of mutagenesis experiments aimed at improving toxicity, and lead to a deep understanding of the mechanism of action of nematicidal toxins.
Cry5Ba是苏云金芽孢杆菌PS86A1 NRRL B - 18900产生的一种δ-内毒素。它对线虫具有活性，在控制线虫方面具有巨大潜力。在此，我们通过对鳞翅目昆虫特异性的Cry1Aa毒素结构进行同源建模，预测了Cry5Ba毒素三维（3D）结构的首个理论模型。Cry5Ba与先前报道的Cry1Aa毒素结构相似，它们具有由三个结构域组成的共同3D结构，但也存在一些差异，主要差异位于结构域I的环区。Cry5Ba呈现出可变的伸展构象结构，这种特殊结构可能也参与了孔形成和特异性的确定。更全面地了解3D结构将有助于设计旨在提高毒性的诱变实验，并深入理解杀线虫毒素的作用机制。
