在二二氧化碳聚酶中对有机酸盐耐药性的结构和进化约束
Rebecca L Frkic1,2, Alex Giang3, Sacha B Pulsford1,4
1Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia.
概括
昆虫对有机酸盐 (OP) 杀虫剂的耐药性是通过α-carboxylesterases (CBEs) 的突变而演变的. 这些突变的有效性取决于特定的酶序列,揭示了OP排毒的复杂进化途径.
科学领域:
- 生物化学 生物化学
- 进化生物学 进化生物学
- 抗虫剂耐药性 抗虫剂耐药性 抗虫剂耐药性
背景情况:
- 有机 (OP) 杀虫剂通过昆虫的α-carboxylesterases (CBEs) 进行排毒.
- 在CBE氧化离子孔中的特定突变 (G→D) 增强了OP水解,并赋予了一些二体物种的耐药性.
- 这种抵抗机制的进化基础和局限性尚未完全理解.
研究的目的:
- 为了研究CBE中G137D突变的序列上下文依赖性,用于有机酸盐水解.
- 探索催化OP电阻中的进化偶然性和表现性.
- 了解进一步的突变如何优化OP排毒及其转化为昆虫耐药性.
主要方法:
- 对OP水解速率的系统比较和对两动物物种CBE正方体的结构分析.
- 实验室指导的进化产生高周转率的CBE变种.
- 测试转基因 * Drosophila melanogaster * 中的进化变体,以评估耐药性.
主要成果:
- 在增强OP水解方面G137D突变的有效性取决于周围的氨基酸序列 (上下文依赖).
- 与野生型CBE相比,定向进化实现了OP营业额的1000倍以上的增长.
- 进化CBE中增强的催化速率与转基因D. melanogaster的抗性增加没有直接相关.
- 在OP绑定亲和力和催化周转率之间存在一个权衡.
结论:
- 通过CBE修改的OP电阻的演变受到序列上下文的约束,并涉及复杂的权衡.
- 优化的催化效率并不能保证由于其他生物因素而提高昆虫的抗性.
- 了解这些进化动态对于预测抗虫剂耐药性的传播至关重要.
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