Université Paris Cité, Laboratoire de Biochimie Théorique CNRS UPR9080, Paris, 75005, France.
Institut de Biologie Physico-Chimique, Fondation Edmond de Rothschild, Paris, 75005, France.
Nat Commun. 2023 May 5;14(1):2594. doi: 10.1038/s41467-023-38219-9.
Brown adipose tissue expresses uncoupling protein 1 (UCP1), which dissipates energy as heat, making it a target for treating metabolic disorders. Here, we investigate how purine nucleotides inhibit respiration uncoupling by UCP1. Our molecular simulations predict that GDP and GTP bind UCP1 in the common substrate binding site in an upright orientation, where the base moiety interacts with conserved residues R92 and E191. We identify a triplet of uncharged residues, F88/I187/W281, forming hydrophobic contacts with nucleotides. In yeast spheroplast respiration assays, both I187A and W281A mutants increase the fatty acid-induced uncoupling activity of UCP1 and partially suppress the inhibition of UCP1 activity by nucleotides. The F88A/I187A/W281A triple mutant is overactivated by fatty acids even at high concentrations of purine nucleotides. In simulations, E191 and W281 interact with purine but not pyrimidine bases. These results provide a molecular understanding of the selective inhibition of UCP1 by purine nucleotides.
棕色脂肪组织表达解偶联蛋白 1（UCP1），它将能量以热量的形式散发，使其成为治疗代谢紊乱的目标。在这里，我们研究嘌呤核苷酸如何通过 UCP1 抑制呼吸解偶联。我们的分子模拟预测 GDP 和 GTP 以直立的方式结合 UCP1 在共同的底物结合位点，碱基部分与保守残基 R92 和 E191 相互作用。我们确定了一组不带电荷的残基 F88/I187/W281，与核苷酸形成疏水性接触。在酵母原生质体呼吸测定中，I187A 和 W281A 突变体均增加 UCP1 诱导的脂肪酸解偶联活性，并部分抑制核苷酸对 UCP1 活性的抑制。即使在嘌呤核苷酸的高浓度下，F88A/I187A/W281A 三突变体也被脂肪酸过度激活。在模拟中，E191 和 W281 与嘌呤而不是嘧啶碱基相互作用。这些结果提供了对嘌呤核苷酸对 UCP1 选择性抑制的分子理解。
