PDF(Pubmed)
Abstract：
Ferrochelatase (FECH) is the terminal enzyme in human heme biosynthesis, catalyzing the insertion of ferrous iron into protoporphyrin IX (PPIX) to form protoheme IX (Heme). Phosphorylation increases the activity of FECH, and it has been confirmed that the activity of FECH phosphorylated at T116 increases. However, it remains unclear whether the T116 site and other potential phosphorylation modification sites collaboratively regulate the activity of FECH. In this study, we identified a new phosphorylation site, T218, and explored the allosteric effects of unphosphorylated (UP), PT116, PT218, and PT116 + PT218 states on FECH in the presence and absence of substrates (PPIX and Heme) using molecular dynamics (MD) simulations. Binding free energies were evaluated with the MM/PBSA method. Our findings indicate that the PT116 + PT218 state exhibits the lowest binding free energy with PPIX, suggesting the strongest binding affinity. Additionally, this state showed a higher binding free energy with Heme compared to UP, which facilitates Heme release. Moreover, employing multiple analysis methods, including free energy landscape (FEL), principal component analysis (PCA), dynamic cross-correlation matrix (DCCM), and hydrogen bond interaction analysis, we demonstrated that phosphorylation significantly affects the dynamic behavior and binding patterns of substrates to FECH. Insights from this study provide valuable theoretical guidance for treating conditions related to disrupted heme metabolism, such as various porphyrias and iron-related disorders.
摘要：
铁螯合酶(FECH)是人血红素生物合成的末端酶,催化亚铁插入原卟啉IX（PPIX）以形成原血红素IX（血红素）。磷酸化增加FECH的活性，并且已经证实在T116磷酸化的FECH的活性增加。然而,目前尚不清楚T116位点和其他潜在的磷酸化修饰位点是否协同调节FECH的活性.在这项研究中,我们发现了一个新的磷酸化位点,T218，并探索了非磷酸化（UP）的变构效应，PT116、PT218和PT116+PT218使用分子动力学(MD)模拟在存在和不存在底物(PPIX和血红素)的情况下在FECH上陈述。用MM/PBSA方法评估结合自由能。我们的发现表明，PT116+PT218状态与PPIX表现出最低的结合自由能，表明最强的结合亲和力。此外,与UP相比，这种状态显示出更高的与血红素的结合自由能，这有利于血红素的释放。此外，采用多种分析方法，包括自由能源景观（FEL），主成分分析(PCA)，动态互相关矩阵(DCCM)和氢键相互作用分析，我们证明磷酸化显著影响底物与FECH的动态行为和结合模式。本研究的见解为血红素代谢紊乱相关疾病的治疗提供了有价值的理论指导。如各种卟啉病和铁相关疾病。
