Role of cysteine at positions 67, 161 and 241 of a Bacillus sphaericus binary toxin BinB
Role of cysteine at positions 67, 161 and 241 of a Bacillus sphaericus binary toxin BinB
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DOI：
10.5483/bmbrep.2010.43.1.023
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发表时间：
2010-01-31
期刊：
影响因子：
3.8
通讯作者：
Promdonkoy, Boonhiang
中科院分区：
文献类型：
--
作者：
Boonyos, Patcharaporn;Soonsanga, Sumarin;Promdonkoy, Boonhiang
来自球形芽孢杆菌的 BinA 和 BinB 组成的二元毒素对蚊子幼虫有毒。 BinB 负责与幼虫肠道细胞膜的特异性结合，而 BinA 对于毒性至关重要。为了研究 BinB 中半胱氨酸的功能作用，将 67、161 和 241 位的三个半胱氨酸残基替换为丙氨酸或丝氨酸。这些位置的突变不会影响 BinB 的蛋白质生产和整体结构。这些半胱氨酸残基不参与 BinB 分子之间二硫键的形成。杀蚊幼虫试验表明，C67 和 C161 对于毒性至关重要，而 C241 则不然。C67 和 C161 的突变导致 BinA-BinB 相互作用较弱。毒性的丧失可能是由于BinA和BinB或BinB与其受体之间的相互作用减少所致。 C67 和 C161 也可能在二元毒素构象变化或内化到靶细胞中的过程中发挥作用。 [BMB 2010 年报告； 43（1）：23-28]
Binary toxin consisting of BinA and BinB from Bacillus sphaericus is toxic to mosquito larvae. BinB is responsible for specific binding to the larval gut cell membrane while BinA is crucial for toxicity. To investigate functional role of cysteine in BinB, three cysteine residues at positions 67, 161, and 241 were replaced by alanine or serine. Mutations at these positions did not affect protein production and overall structure of BinB. These cysteine residues are not involved in disulfide bond formation between BinB molecules. Mosquito-larvicidal assays revealed that C67 and C161 are essential for toxicity, whereas C241 is not Mutations at C67 and C161 resulted in weaker BinA-BinB interaction. The loss of toxicity may be due to the reduction of interactions between BinA and BinB or BinB and its receptor. C67 and C161 could also play a part during conformational changes or internalization of the binary toxin into the target cell. [BMB reports 2010; 43(1): 23-28]