Wang Dianzhuo, Gottinger Andrea, Jeong Jio, Nicoll Callum R, Liu Junlang, Kadavá Tereza, Cecchini Domiziana, Malatesta Marco, Heck Albert J R, Mattevi Andrea, Shakhnovich Eugene I
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA.
These authors contributed equally.
bioRxiv. 2025 May 28:2025.05.24.655883. doi: 10.1101/2025.05.24.655883.
Metabolons - transient assemblies of sequential metabolic enzymes - facilitate the reactions of multi-step metabolic pathways, yet, how they mechanistically bolster metabolic flux remains unknown. Here, we investigate the molecular determinants of metabolon formation in coenzyme Q (CoQ) biosynthesis using coarse-grained molecular dynamics simulations and biochemical experiments. We show that the COQ metabolon forms at the critical region of a phase transition, where both metabolon clustering and metabolic flux exhibit coordinated sigmoidal responses to changes in protein-protein interaction strength. These complete metabolons enable substrate channeling between sequential enzymes, leading to a crucial enhancement of CoQ production efficiency. Selectively disrupting protein-protein interactions and randomly shuffling the interaction network demonstrate that protein-proximity rather than fine structure of the metabolon clusters is imperative for substrate channeling. Grounded in both experiment and simulation, these findings provide a framework for understanding the organization and function of metabolons across diverse metabolic pathways.
代谢体——顺序代谢酶的瞬时组装体——促进多步代谢途径的反应，然而，它们如何从机制上增强代谢通量仍不清楚。在这里，我们使用粗粒度分子动力学模拟和生化实验研究辅酶Q（CoQ）生物合成中代谢体形成的分子决定因素。我们表明，COQ代谢体在相变的关键区域形成，在该区域，代谢体聚集和代谢通量对蛋白质-蛋白质相互作用强度的变化都表现出协调的S形响应。这些完整的代谢体能够在顺序酶之间进行底物通道化，从而显著提高CoQ的生产效率。选择性破坏蛋白质-蛋白质相互作用并随机改组相互作用网络表明，对于底物通道化来说，蛋白质的接近程度而非代谢体簇的精细结构至关重要。基于实验和模拟，这些发现为理解不同代谢途径中代谢体的组织和功能提供了一个框架。
