一个截断的人类GlcNAc-1-phosphotransferase变体的结构揭示了其过活性的基础
Hua Li1, Balraj Doray2, Benjamin C Jennings2
1Department of Structural Biology, Van Andel Institute, Grand Rapids, Michigan, USA.
The Journal of biological chemistry
|August 23, 2024
概括
失去GlcNAc-1-转化酶 (PTase) 会导致II型粘脂症. 这项研究揭示了一种过度活跃的PTase变体的冷-EM结构,详细介绍了其催化核心和相互作用,这对于了解 lysosomal酶向至关重要.
科学领域:
- 生物化学 生物化学
- 结构生物学 结构生物学
- 细胞生物学 细胞生物学
背景情况:
- 在GlcNAc-1-phosphotransferase (PTase) 中的突变会导致II型粘脂症,一种溶酶体储存障碍.
- 聚酶对于-6酸盐 (M6P) 标记系统至关重要,它将 lysosomal 酸酶引导到 lysosomes.
- 一个先前生成的截断,过活跃的PTase变体 (S1S3) 增强了 lysosomal酶酸化和细胞吸收.
研究的目的:
- 为了确定可溶性,截断过活的PTase变体 (S1S3) 的冷电子显微镜 (cryo-EM) 结构.
- 阐明S1S3结构中的分子相互作用以及 UDP-GlcNAc 在全长可溶蛋白中的分子相互作用.
- 为了比较S1S3的域组织与它的Drosophila melanogaster同类.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 确定可溶性S1S3 PTase变体的3.4 Å结构.
- 高质量的EM3D地图生成,用于与UDP-GlcNAc.结合的全长可溶蛋白.
- 人类PTase同类和Drosophila melanogaster PTase之间的结构比较.
主要成果:
- 溶性S1S3的冷-EM结构显示了一个保存的催化核心和特定的原质子相互作用 (EF手与保存区域四).
- 全长可溶性PTase的UDP-GlcNAc结合结构显示了与核酸糖供体的关键相互作用.
- 德洛索菲拉黑龙的PTase同源与S1S3共享域组织,但不准溶解体水解酶.
结论:
- 过度活跃的S1S3 PTase变体的结构为保存的催化机制提供了洞察力.
- 了解PTase的结构和功能对于解决II型粘脂症至关重要.
- 人类和果PTase同类物之间存在功能差异,尽管结构相似.
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