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生物化学,生物物理和结构分析来自极端爱好者Deinococcus radiodurans的一个不寻常的DYP

Kelly Frade¹, Célia M Silveira¹, Bruno A Salgueiro¹

¹Instituto de Tecnologia Química e Biológica António Xavier (ITQB-NOVA), Universidade Nova de Lisboa, Av. da Republica (EAN), 2780-157 Oeiras, Portugal.

Molecules (Basel, Switzerland)

|January 23, 2024

概括

来自Deinococcus radiodurans的染料脱色过氧化酶 (DyPs) 在生理pH下由于血红素结合而无活性. 结构分析显示,一种基连接体,而不是甲氨酸,可能会阻断这种耐辐射细菌的基质结合.

科学领域:

生物化学生物化学
酶学是一种酶学.
结构生物学结构生物学

背景情况:

染色脱色过氧化酶 (DyP) 是具有独特结构和基质特异性的血红蛋白.
DyPs不同于经典的过氧化酶,一些同类物表现出pH依赖的活性.

研究的目的:

研究来自Deinococcus radiodurans (DrDyP) 的Dyp的pH依赖活性.
确定在生理pH值下DrDyP无活性的结构基础.
评估一种特定的氨酸残留物在DrDyP活动中的作用.

主要方法:

共振拉曼 (RR) 和UV-VIS光谱学以分析血协调和旋转状态.
位点定向的突变发生,以用甘氨酸替代甲胺.
进行X射线晶体学以确定DrDyP及其突变的结构.

主要成果:

在pH 7.5下,DrDyP是不活跃的,其血质处于六协调低旋转 (6cLS) 状态,无法与过氧化结合.
在pH4.0下观察到对H2O2的催化活性,与混合的高旋转和低旋转血状态相关.
在位置190的甲氨酸残留物在pH7.5.5下不会影响酶的自旋状态或活性.
晶体结构显示,在pH 8.5的DrDyPM190G中有一个基和一个水分子,强烈结合了血和催化残留物,可能阻碍了H2O2结合.

结论:

在生理pH值下DrDyP的不活性主要是由于基联结体,而不是氨酸残留物.
这些发现引发了关于DrDyP和其他DYP的生理基质的问题.
了解这种基联体的调节是释放DrDyP催化潜力的关键.

关键词:

在X射线晶体学.染料去色的过氧化酶.黑姆蛋白质是什么黑姆蛋白质是什么共振拉曼光谱法拉曼光谱法

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