The CNNM/CorC Mg²⁺ transporters are widely conserved in eukaryotes (cyclin M [CNNM]) and prokaryotes (CorC) and participate in various biological processes. Previous structural analyses of the CorC transmembrane domain in the Mg²⁺-bound inward-facing conformation revealed the conserved Mg²⁺ recognition mechanism in the CNNM/CorC family; however, the conformational dynamics in the Mg²⁺ transport cycle remain unclear because structures in other conformations are unknown. Here, we used AlphaFold structure prediction to predict the occluded-like and outward-facing-like conformations of the CorC and CNNM proteins and identified conserved hydrophilic interactions close to the cytoplasmic side in these conformations. Molecular dynamics simulations and biochemical cross-linking showed that these conserved hydrophilic interactions are stable, especially in the outward-facing-like conformation. Furthermore, mutational analysis revealed that the residues involved in these hydrophilic interactions on the cytoplasmic side are important for Mg²⁺ transport in the CorC and CNNM proteins. Our work provides mechanistic insights into the transport cycle of the CNNM/CorC family.

中文翻译：

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CNNM/CorC Mg2+ 转运蛋白构象动力学的 AI 驱动机制分析


CNNM/CorC Mg²⁺ 转运蛋白在真核生物 （cyclin M [CNNM]） 和原核生物 （CorC） 中广泛保守，并参与各种生物过程。先前对 Mg²⁺ 结合的内向构象中 CorC 跨膜结构域的结构分析揭示了 CNNM/CorC 家族中保守的 Mg²⁺ 识别机制;然而，Mg²⁺ 转运周期中的构象动力学仍然不清楚，因为其他构象的结构是未知的。在这里，我们使用 AlphaFold 结构预测来预测 CorC 和 CNNM 蛋白的闭塞样和外向样构象，并确定了这些构象中靠近细胞质侧的保守亲水相互作用。分子动力学模拟和生化交联表明，这些保守的亲水相互作用是稳定的，尤其是在朝外的构象中。此外，突变分析表明，细胞质侧参与这些亲水相互作用的残基对 CorC 和 CNNM 蛋白中的 Mg²⁺ 转运很重要。我们的工作为 CNNM/CorC 家族的运输周期提供了机制见解。