结构,生物物理和生物化学洞察力,通过二甲基硫单氧基酶对C-S键裂解
Reyaz Gonzalez1, Jess Soule1, Ngan Phan2
1Department of Chemistry, University of Massachusetts, Boston, MA 02125.
概括
伪虫使用SfnG酶来分解二甲基硫 (DMSO2) 进行硫同化. 结构研究揭示了SfnGG.
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:
- 硫对生命至关重要,像Pseudomonads这样的细菌从各种环境化合物中同化它.
- 来自msu和sfn操作子的双组分黄素依赖单氧酶 (TC-FMOs) 在硫饥饿期间对硫同化至关重要.
- 甲基硫 (DMSO2) 是这些细菌利用的关键环境硫化合物.
研究的目的:
- 调查P. fluorescens中负责将DMSO2转化为硫酸盐的酶途径.
- 为了阐明SfnG的结构和功能,这个硫同化途径中的初始TC-FMO.
- 了解SfnG酶内的FMN和DMSO2的结合相互作用.
主要方法:
- 使用X射线晶体学来确定未结合的SfnG及其与FMN和DMSO2.2的三元复合物的结构.
- 染色学和光散射评估了结构异质性,并证实了联体诱导的四聚体形成.
- 使用功能测试,生化终点测试和对接研究来检测酶活性和基质结合.
主要成果:
- SfnG 具有 (β/α) 8 桶折叠,具有独特的四度四度结构,与其他 C 类 TC-FMOs 不同.
- 干结合 (FMN和DMSO2) 诱导了活性位点的排序,DMSO2 与黄素的si面结合.
- 在氧结合部位观察到一种新的蛋白质骨干构造,这表明了N5-(水) 氧黄机制.
- SfnG有效地打破了各种dialkylsulfones中的碳硫键.
结论:
- 在细菌从dialkylsulfones吸收硫中,SfnG起着至关重要的作用.
- 确定的结构提供了关于催化机制的见解,包括基质结合和C-S键裂解.
- 这些发现揭示了Pseudomonads中硫化合物代谢的独特酶结构和机制.
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