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在循环GMP-AMP合成酶中诱导Mn2+催化物的光谱表征

Karis Williamson¹, Karina Sharafutdinova¹, Micah Gaddy¹

¹Department of Chemistry and Biochemistry, Howard College of Arts and Sciences, Samford University, 800 Lakeshore Drive, Birmingham, AL 35229, USA.

Journal of inorganic biochemistry

|December 23, 2025

概括

(Mn2+) 显著增强循环GMP-AMP合成酶 (cGAS) 活性,促进先天免疫信号传递. 这项研究揭示了Mn2+协调及其在cGAS激活中的作用,独立于DNA存在.

科学领域:

生物化学生物化学
分子生物学分子生物学
免疫学免疫学免疫学

背景情况:

循环GMP-AMP合成酶 (cGAS) 是细胞质双链DNA (dsDNA) 的关键传感器,通过产生2'3'-cGAMP.产生先天免疫反应.
规范激活涉及Mg2+,但Mn2+已经成为一个强大的辅助因子,影响催化,选择性和产品保真.
在cGAS激活中Mn2+的确切作用及其在活性位点内的协调仍然不完全理解.

研究的目的:

使用生物物理技术研究cGAS活性部位内的Mn2+协调.
阐明Mn²⁺介导的催化增强和cGAS的dsDNA独立激活的分子基础.
定义金属辅助因子在调节cGAS介导的先天免疫信号传递中的机械作用.

主要方法:

使用液体染色学-并联质谱法 (LC-MS/MS) 来分析cGAS活性.
电子偏磁共振 (EPR) 光谱,包括电子自旋回声封膜调制 (ESEEM) 和电子核双共振 (ENDOR),用于探测Mn2+协调.
用Mg²⁺和Mn²⁺进行了催化活性测试,在dSDNA的存在和缺乏的情况下.

主要成果:

与Mg2+-cGAS相比,Mn2+-cGAS具有 (六倍) 和没有 (十四倍) dsDNA的催化活性显著更高.
EPR光谱显示,Mn2+在基质结合的cGAS复合体中由ATP和蛋白质配体协调.
在活性部位组装过程中观察到2+的吸收,这表明它在酶激活中起着至关重要的作用.

结论:

这项研究提供了cGAS中Mn2+协调的第一个光谱表征,提供了关键的机械洞察力.
2+作为一种优选的辅因子,增强了cGAS催化,可以促进dSDNA独立激活,突出其在天生的免疫力中的重要作用.
了解cGAS的金属辅因子调节对于破译其对健康和疾病的更广泛影响至关重要.

关键词:

在EPR光谱学中使用EPR光谱.这是天生的免疫力.的激活方式金属酶催化剂的催化 cGAS 是一个气体.

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