Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego , La Jolla, California 92093, United States.
J Nat Prod. 2014 Jan 24;77(1):92-9. doi: 10.1021/np400727r. Epub 2013 Dec 23.
A number of marine natural products are potent inhibitors of proteases, an important drug target class in human diseases. Hence, marine cyanobacterial extracts were assessed for inhibitory activity to human cathepsin L. Herein, we have shown that gallinamide A potently and selectively inhibits the human cysteine protease cathepsin L. With 30 min of preincubation, gallinamide A displayed an IC50 of 5.0 nM, and kinetic analysis demonstrated an inhibition constant of ki = 9000 ± 260 M(-1) s(-1). Preincubation-dilution and activity-probe experiments revealed an irreversible mode of inhibition, and comparative IC50 values display a 28- to 320-fold greater selectivity toward cathepsin L than closely related human cysteine cathepsin V or B. Molecular docking and molecular dynamics simulations were used to determine the pose of gallinamide in the active site of cathepsin L. These data resulted in the identification of a pose characterized by high stability, a consistent hydrogen bond network, and the reactive Michael acceptor enamide of gallinamide A positioned near the active site cysteine of the protease, leading to a proposed mechanism of covalent inhibition. These data reveal and characterize the novel activity of gallinamide A as a potent inhibitor of human cathepsin L.
许多海洋天然产物是蛋白酶的有效抑制剂，蛋白酶是人类疾病中一个重要的药物靶点类别。因此，评估了海洋蓝细菌提取物对人组织蛋白酶 L 的抑制活性。本文显示，鹅膏蕈氨酸 A 能够强烈且选择性地抑制人类半胱氨酸蛋白酶组织蛋白酶 L。孵育 30 分钟后，鹅膏蕈氨酸 A 的 IC50 为 5.0 nM，动力学分析表明抑制常数 ki = 9000 ± 260 M(-1) s(-1)。预孵育-稀释和活性探针实验揭示了不可逆的抑制模式，比较 IC50 值显示对密切相关的人类半胱氨酸组织蛋白酶 V 或 B 的选择性高 28-320 倍。分子对接和分子动力学模拟用于确定鹅膏蕈氨酸在组织蛋白酶 L 活性位点的构象。这些数据确定了一个构象，其特征为高稳定性、一致的氢键网络以及鹅膏蕈氨酸 A 的反应性迈克尔受体烯酰胺位于蛋白酶的活性位点半胱氨酸附近，导致提出了共价抑制的机制。这些数据揭示并表征了鹅膏蕈氨酸 A 作为人类组织蛋白酶 L 有效抑制剂的新活性。
