活性中心扭转角应变在1.6A分辨率结构中揭示了含有histidine的素载体蛋白质
Z Jia1, M Vandonselaar, J W Quail
1Department of Chemistry, University of Saskatchewan, Saskatoon, Canada.
Nature
|January 7, 1993
概括
含有histidine的载体蛋白 (HPr) 结构揭示了其活性部位的独特扭转角应变. 这种菌株可能会降低激活能量屏障,通过光转移酶系统促进细菌碳水化合物运输.
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:
- 烯酸:糖转移酶系统 (PTS) 对于细菌通过细胞膜运输碳水化合物至关重要.
- 含有histidine的素载体蛋白 (HPr) 是PTS光转移级联中的一个关键中间体.
- 通过使用高能烯酸酸,PTS促进了热力学上有利的糖运输.
研究的目的:
- 为了确定来自Streptococcus faecalis的HPr的高分辨率X射线结构.
- 研究活点扭转角应变在HPr功能和光转移机制中的作用.
- 提出HPr光转移循环的详细机制.
主要方法:
- 使用X射线晶体学以1.6 Å分辨率确定Streptococcus faecalis中的HPr的3D结构.
- 在活动中心分析Ramachandran扭转角,以识别和量化应变.
- 使用来自Bacillus subtilis的HPr进行比较结构分析.
主要成果:
- 菌面膜HPr的X射线结构揭示了活跃中心显著的,不允许的Ramachandran扭转角度,表明了相当大的扭转角度应变.
- 假设这种扭矩角应变降低了酸化过程中光转移的激活能量屏障.
- 与Bacillus subtilis的HPr结构 (酸化状态,没有应变) 的比较支持扭转角应变在HPr活动中的功能作用.
结论:
- 在HPr的活性中心的扭转角应变是直接参与促进光转移反应的关键特征.
- 提出的HPr光转移循环机制得到了HPr和其他PTS蛋白质的结构数据的支持.
- 了解HPr结构-功能关系,可以深入了解细菌碳水化合物代谢和运输调节.
相关概念视频
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Protein and Protein Structure
Proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules. Proteins may be structural, regulatory, contractile, or protective. They may serve in transport, storage, or membranes; or they may be toxins or enzymes. Their structures, like their functions, vary greatly. They are all, however, amino acid polymers arranged in a linear sequence.
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The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...
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Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
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Proteins are polymers of amino acid residues. They are versatile and responsible for different cellular functions, including DNA replication, molecular transport, catalysis, and structural support. Proteins have a hierarchical structure comprising at least three levels of organization: primary, secondary, and tertiary structure. Some large proteins have a quaternary structure where individual protein subunits are linked together.
The primary structure of a protein is its amino acid sequence.
The primary structure of a protein is its amino acid sequence.


