来自青素结合蛋白的β-乳糖酶演化的结构方面
Samy O Meroueh1, George Minasov, Wenlin Lee
1Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
Journal of the American Chemical Society
|August 9, 2003
概括
细菌耐药性酶,β-乳酸酶,进化了不同的活性位点,以防止与丁糖的相互作用,与素结合蛋白不同. 结构分析和模拟证实了废除糖结合的修改,使抗生素耐药性.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 微生物学 微生物学
背景情况:
- 青素结合蛋白 (PBP) 和β-乳糖酶具有共同的进化起源.
- PBPs通过使用peptidoglycan合成细菌细胞壁.
- β-乳糖酶会对β-乳糖抗生素产生耐药性.
研究的目的:
- 研究使β-乳糖酶能够作为抗生素耐药性酶的结构变化.
- 为了测试β-乳糖酶进化以避免与PBPs的基质皮糖甘相互作用的假设.
主要方法:
- 合成一种头松素类似物 (化合物6).
- 进行X射线晶体学以确定头素-AmpCβ-乳糖酶复合物的结构.
- 复杂的分子动力学模拟.
主要成果:
- X射线结构显示,在β-lactamase活性部位中没有丁糖相互作用表面.
- 在β-乳糖酶活性部位的片插入,防止与丁糖链的相互作用.
- 分子动力学模拟显示,结合的连接体没有稳定,表明缺乏特定的结合.
结论:
- β-乳糖酶的结构性修改阻止了与糖的相互作用.
- 这些变化对于酶在抗生素耐药性的催化能力至关重要.
- 这项研究阐明了beta-lactamases与PBPs的进化分歧.
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