膜机器的结构基础,这些机器贩运和将血红素附着在细胞染色体上
Jonathan Q Huynh1, Ethan P Lowder1, Robert G Kranz1
1Department of Biology, Washington University, St. Louis, Missouri, USA.
The Journal of biological chemistry
|October 12, 2023
概括
两个分子机器,CcsBA和CcmF/H,通过不同的机制将血红素连接到细胞染色体c (cyt c). 结构分析揭示了这些细胞合成酶中对血红素贩运和共价附着至关重要的保存域.
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:
- 细胞染色体c (cyt c) 对于细胞呼吸至关重要,并由特定的分子机器合成.
- 血红蛋白与细胞结合是一种关键的翻译后修饰,涉及复杂的蛋白质机制.
- 已知有两种不同的系统,CcsBA和CcmF/H,可以调节血红素与细胞结合.
研究的目的:
- 阐明黑米贩运和CCSBA和CCMF/H.对细胞的依附的结构机制.
- 用冷电子显微镜 (cryoEM) 和晶体结构分析这些血附着机器的功能领域和保存特征.
- 为了比较CCSBA和CCMF/H用于血红素输送和共价链接的不同途径.
主要方法:
- 低温电子显微镜 (cryo-electron microscopy,cryoEM) 和结晶结构测定CcsBA和CcmF/H复合物的方法.
- 对各种生物体中保存的域和蛋白质序列的生物信息分析.
- 生物化学试验,以研究血红素的降解和附着机制.
主要成果:
- 该CcsBA复合体形成一个运输到外部活性部位的通道,利用WWD序列和histidines通过乙烯键进行共价附着.
- 在CcsBA内保留的口袋促进了立体特异的血结合,而周等离子体β盖结构保护了活性部位.
- 通过周等离子体入口,CCMF/H接收Fe+3,CCMF起到还原酶的作用,促进向其WWD/P-His域的插入.
结论:
- CcsBA和CcmF/H采用不同的血红素输送和对细胞的共价附着策略.
- 结构洞察力揭示了关键的功能领域,包括保存的口袋和保护结构,对于结和修饰至关重要.
- 这些发现有助于我们更好地理解控制多种生命形式中细胞染色体成熟和功能的复杂过程.
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