塑原结合M蛋白D域中的疏水性残留物调节了Streptococcus pyogenes中的α-helicity,寡合化和表面定
Olawole Ayinuola1, Yetunde A Ayinuola1, Zhong Liang1
1W.M. Keck Center for Transgene Research, Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA.
Protein science : a publication of the Protein Society
|September 13, 2025
概括
M-蛋白D域对A组链球菌的毒性至关重要,影响蛋白质结构,细菌细胞表面的附着和人类等离子体激活. 突变破坏了这些功能,影响了GAS的发病.
科学领域:
- 微生物学 微生物学
- 结构生物学 结构生物学
- 蛋白质生物化学 蛋白质生物化学
背景情况:
- 来自A组链球菌 (GAS) 的M蛋白 (PAM) 是一种关键的毒性因子,它结合人体等离子素 (hPg).
- PAM的C和D域含有不规则的七度重复,采用特定的结构图案,而不是典型的卷轴.
- 在PAM结构和功能中D域的作用仍然在很大程度上未被描述.
研究的目的:
- 研究GAS中M蛋白D域的结构和功能意义.
- 阐明D域对PAM二级/四级结构,细菌表面显示和hPg激活的贡献.
主要方法:
- 三种PAM变体 (PAMAP53-9G,PAMAP53-9A,PAMAP53-9L) 的结构引导工程,通过用甘氨酸,氨酸或白氨酸替换D域残留物.
- 对蛋白质寡合化,热稳定性和hPg结合亲和力的分析.
- 评估hPg激活的链球酶 (SK2b) 和细菌表面显示的工程PAM变体.
主要成果:
- 野生型PAMAP53形成温度依赖的寡合体,而PAMAP53-9A和PAMAP53-9L形成恒温的寡合体,而PAMAP53-9G存在于具有减少螺旋含量的单体.
- 所有变体都保持了高的hPg结合亲和力.
- 与WT-PAMAP53,PAMAP53-9A和PAMAP53-9L不同,PAMAP53-9G表现出受损的hPg激活,并且未能在GAS细胞表面显示.
结论:
- M蛋白D域对于维持PAM的二次/四次结构和热稳定性至关重要.
- 对于 PAM 与 GAS 细胞壁的共价附着,D 域完整性至关重要.
- D域在促进SK2b介导的hPg激活中发挥着至关重要的作用,这是一个关键的GAS毒性机制.
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