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鱼血红蛋白独特的全精性质通过冷EM阐明

Katsuya Takahashi¹, Yongchan Lee¹, Angela Fago²

¹Graduate School of Medical Life Science, Yokohama City University, Suehiro 1-7-29, Yokohama, 230-0045, Japan.

Nature communications

|August 1, 2024

概括

鱼血红蛋白独特地与二碳酸盐结合,降低了长时间潜水时的氧气亲和力. 这项研究揭示了冷EM结构,解释了它们T状态血红蛋白中的这种独特的全调节.

科学领域:

生物化学生物化学
结构生物学结构生物学
进化生物学进化生物学

背景情况:

脊椎动物的血红蛋白 (Hb) 功能主要由高亲和度R和低亲和度T状态之间的异质过渡来控制.
鱼表现出一种独特的Hb特性:在二碳酸离子结合时,氧 afinity显著下降.
这种双碳酸诱导的效应有助于延长水下潜水,通过增强从血液中提取氧气.

研究的目的:

阐明二碳酸盐对鱼血红蛋白的全调节背后的分子机制.
为了比较人类和鱼Hb在脱氧和结合状态的结构基础.
确定二碳酸盐离子与鱼Hb.的特定结合点和相互作用.

主要方法:

使用冷电子显微镜 (cryo-EM) 确定人类和鱼Hb的高分辨率分子结构.
在脱氧 (无氧) 和结合 (有氧结合) 状态下分析结构.
专注于确定精确的蛋白质效应因子相互作用,特别是与二碳酸盐离子.

主要成果:

揭示了两个二碳酸盐离子与鱼Hb.的精确结合相互作用.
确定了独特的二碳酸盐结合点,位于与对称性相关的位置,仅限于鱼Hb.的T状态.
观察到这些二碳酸盐结合点与任何其他已知的脊椎动物Hb全效应物的结合点不同.

结论:

双碳酸盐作为鱼Hb中独特的全调节剂,在特定的T状态部位结合.
这种独特的结合机制解释了在鱼中观察到的氧 afinity 的严重下降.
这种二碳酸盐结合性质的演化是鱼在脊椎动物中独有的.

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