Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China.
J Mol Model. 2012 Aug;18(8):3831-45. doi: 10.1007/s00894-012-1381-8. Epub 2012 Mar 9.
Cannabinoid receptor-1 (CB(1)) is widely expressed in the central nervous system and plays a vital role in regulating food intake and energy expenditure. CB(1) antagonists such as Rimonabant have been used in clinic to inhibit food intake, and therefore reduce body weight in obese animals and humans. To investigate the binding modes of CB(1) antagonists to the receptor, both receptor- and ligand-based methods were implemented in this study. At first, a pharmacophore model was generated based on 31 diverse CB(1) antagonists collected from literature. A test set validation and a simulated virtual screening evaluation were then performed to verify the reliability and discriminating ability of the pharmacophore. Meanwhile, the homology model of CB(1) receptor was constructed based on the crystal structure of human β (2) adrenergic receptor (β (2)-AR). Several classical antagonists were then docked into the optimized homology model with induced fit docking method. A hydrogen bond between the antagonists and Lys192 on the third transmembrane helix of the receptor was formed in the docking study, which has proven to be critical for receptor-ligand interaction by biological experiments. The structure obtained from induced fit docking was then confirmed to be a reliable model for molecular docking from the result of the simulated virtual screening. The consistency between the pharmacophore and the homology structure further proved the previous observation. The built receptor structure and antagonists' pharmacophore should be useful for the understanding of inhibitory mechanism and development of novel CB(1) antagonists.
大麻素受体 1(CB1)广泛表达于中枢神经系统,在调节摄食和能量消耗方面发挥着重要作用。CB1 拮抗剂如利莫那班已在临床上用于抑制摄食,从而减少肥胖动物和人类的体重。为了研究 CB1 拮抗剂与受体的结合模式,本研究同时采用基于受体和基于配体的方法。首先,基于文献中收集的 31 种不同的 CB1 拮抗剂,生成了一个药效团模型。然后进行测试集验证和模拟虚拟筛选评估,以验证药效团的可靠性和区分能力。同时,基于人β2 肾上腺素能受体(β2-AR)的晶体结构构建了 CB1 受体的同源模型。然后,用诱导契合对接方法将几种经典拮抗剂对接入优化后的同源模型中。在对接研究中,拮抗剂与受体第三跨膜螺旋上的 Lys192 之间形成氢键,这已被生物实验证明对受体-配体相互作用至关重要。从模拟虚拟筛选的结果来看,诱导契合对接得到的结构被证实是分子对接的可靠模型。药效团和同源结构的一致性进一步证明了之前的观察结果。构建的受体结构和拮抗剂的药效团应该有助于理解抑制机制和开发新型 CB1 拮抗剂。