在Sphingomonas sp.中的谷氨结合中的结构性保护. 葡萄糖素Grx3和变化适应寒冷的变化
Trang Van Tran1, Hoa Nguyen1, Luyen Vu1
1Department of Biomedical Science and Center for Bio-Nanomaterials, Daegu University, Gyeongsan 38453, South Korea.
Biochimica et biophysica acta. Proteins and proteomics
|November 7, 2023
概括
谷氨基素3 (Grx3) 使用关键键键键保持结构和谷氨基结合. 适应寒冷的变种改变了这些键,减少了结合,增加了在低温下生存的灵活性.
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:
- 谷氨素3 (Grx3) 是一种具有氧折的氧化还原蛋白,对于保持结构完整性和跨温度结合谷氨 (GSH) 至关重要.
- 对于GSH结合至关重要的cis-Pro循环,依赖于Arg-Asp盐桥和Gln-His键的构成.
- 心理友好型的Grx3变体通常具有像Arg到Tyr和His到Phe这样的替代,这表明它们适应寒冷的环境.
研究的目的:
- 研究Arg-Asp盐桥和Gln-His键在Grx3结构,功能和冷适应中的作用.
- 分析特定突变对来自北极细菌Sphingomonas sp. 的SpGrx3的影响.
- 了解Grx3中的结构变化如何有助于在寒冷息地生存.
主要方法:
- 用局部导向的突变发生法来创建SpGrx3.3.中的特定氨基酸替代物.
- 评估了野生型和突变蛋白质的结构完整性和GSH结合能力.
- 测量了变种的热稳定性和催化效率.
- 分析了形状变化和相互作用,包括盐桥和键.
主要成果:
- 在SpGrx3.3.中,Arg51-Asp69盐桥和Gln56-His63键对于稳定cis-Pro循环和催化活性至关重要.
- 破坏盐桥 (R51Y) 或键 (Q56A,H63A,H63F) 的突变降低了热稳定性和催化效率.
- 在His63 (H63F,H63Y) 的替代阻碍了通过阴离子-π 相互作用的盐桥,增加了灵活性.
- 一种心理友好型变体 (A48T/R51Y/H63F) 使用Thr48-Gln56键来稳定cis-Pro循环,通过破坏其他关键键键键键键来增强灵活性.
结论:
- 保存的Arg51-Asp69盐桥和Gln56-His63键对于Grx3的功能和结构稳定性至关重要.
- 由于避免与Arg51.1.的不良阴离子-π相互作用,His63比Phe63/Tyr63更受欢迎.
- 心理友好的Grx3变体通过降低GSH结合亲和力和增加结构灵活性来适应寒冷.
- 这些发现阐明了Grx3对GSH结合的结构性保护以及寒冷适应的分子基础.
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