School of Medicine, Center for Infectious Disease Research, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Advanced Innovation Center for Structural Biology.
School of Pharmaceutical Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Tsinghua University, Beijing, China; and.
FASEB J. 2018 Apr;32(4):2036-2045. doi: 10.1096/fj.201700397RR. Epub 2018 Jan 5.
The human kynurenine 3-monooxygenase (hKMO) is a potential therapeutic target for neurodegenerative and neurologic disorders. Inhibition of KMO by Ro 61-8048, a potent, selective, and the most widely used inhibitor of KMO, was shown effective in various models of neurodegenerative or neurologic disorders. However, the molecular basis of hKMO inhibition by Ro 61-8048 is not clearly understood. Here, we report biochemistry studies on hKMO and crystal structures of an hKMO homolog, pfKMO from Pseudomonas fluorescens, in complex with the substrate l-kynurenine and Ro 61-8048. We found that the C-terminal ∼110 aa are essential for the enzymatic activity of hKMO and the homologous C-terminal region of pfKMO folds into a distinct, all-α-helical domain, which associates with the N-terminal catalytic domain to form a unique tunnel in proximity to the substrate-binding pocket. The tunnel binds the Ro 61-8048 molecule, which fills most of the tunnel, and Ro 61-8048 is hydrogen bonded with several completely conserved residues, including an essential catalytic residue. Modification of Ro 61-8048 and biochemical studies of the modified Ro 61-8048 derivatives suggested that Ro 61-8048 inhibits the enzyme in an allosteric manner by affecting the conformation of the essential catalytic residue and by blocking entry of the substrate or product release. The unique binding sites distinguish Ro 61-8048 as a noncompetitive and highly selective inhibitor from other competitive inhibitors, which should facilitate further optimization of Ro 61-8048 and the development of new inhibitory drugs to hKMO.-Gao, J., Yao, L., Xia, T., Liao, X., Zhu, D., Xiang, Y. Biochemistry and structural studies of kynurenine 3-monooxygenase reveal allosteric inhibition by Ro 61-8048.
人类犬尿氨酸 3-单加氧酶（hKMO）是神经退行性和神经疾病的潜在治疗靶点。Ro 61-8048 是一种有效的、选择性的、最广泛使用的 KMO 抑制剂，它对神经退行性或神经疾病的各种模型均显示出有效性，通过抑制 KMO 来发挥作用。然而，Ro 61-8048 抑制 hKMO 的分子基础尚不清楚。在这里，我们报告了犬尿氨酸 3-单加氧酶的生物化学研究以及来自荧光假单胞菌的 pfKMO 同系物的晶体结构，该结构与底物 l-犬尿氨酸和 Ro 61-8048 复合。我们发现，C 端约 110 个氨基酸对于 hKMO 的酶活性至关重要，并且 pfKMO 的同源 C 端区域折叠成一个独特的、全α-螺旋结构域，该结构域与 N 端催化结构域结合，在靠近底物结合口袋的地方形成一个独特的隧道。该隧道结合 Ro 61-8048 分子，该分子填充了大部分隧道，并且 Ro 61-8048 与几个完全保守的残基形成氢键，包括一个必需的催化残基。Ro 61-8048 的修饰和修饰的 Ro 61-8048 衍生物的生化研究表明，Ro 61-8048 通过影响必需催化残基的构象以及通过阻断底物或产物释放来以变构方式抑制该酶。独特的结合位点将 Ro 61-8048 与其他竞争性抑制剂区分开来，使其成为非竞争性和高度选择性的抑制剂，这应该有助于进一步优化 Ro 61-8048 并开发新的抑制性药物来靶向 hKMO。-高，J.，姚，L.，夏，T.，廖，X.，朱，D.，项，Y. 犬尿氨酸 3-单加氧酶的生化和结构研究揭示了 Ro 61-8048 的变构抑制。
