Kim Y C, Gallo-Rodriguez C, Jang S Y, Nandanan E, Adams M, Harden T K, Boyer J L, Jacobson K A
Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0810, USA.
J Med Chem. 2000 Feb 24;43(4):746-55. doi: 10.1021/jm9905211.
P2Y(1) receptors are activated by ADP and occur on endothelial cells, smooth muscle, epithelial cells, lungs, pancreas, platelets, and in the central nervous system. With the aid of molecular modeling, we have designed nucleotide analogues that act as selective antagonists at this subtype. The present study has tested the hypothesis that acyclic modifications of the ribose ring, proven highly successful for nucleoside antiviral agents such as gancyclovir, are generalizable to P2Y receptor ligands. Specifically, the binding site of the P2Y(1) receptor was found to be sufficiently accommodating to allow the substitution of the ribose group with acyclic aliphatic and aromatic chains attached to the 9-position of adenine. Three groups of adenine derivatives having diverse side-chain structures, each containing two symmetrical phosphate or phosphonate groups, were prepared. Biological activity was demonstrated by the ability of the acyclic derivatives to act as agonists or antagonists in the stimulation of phospholipase C in turkey erythrocyte membranes. An acyclic N(6)-methyladenine derivative, 2-[2-(6-methylamino-purin-9-yl)-ethyl]-propane-1, 3-bisoxy(diammoniumphosphate) (10), containing an isopentyl bisphosphate moiety, was a full antagonist at the P2Y(1) receptor with an IC(50) value of 1.60 micro¿. The corresponding 2-Cl derivative (11) was even more potent with an IC(50) value of 0.84 microM. Homologation of the ethylene group at the 9-position to 3-5 methylene units or inclusion of cis- or trans-olefinic groups greatly reduced antagonist potency at the P2Y(1) receptor. Analogues containing a diethanolamine amide group and an aryl di(methylphosphonate) were both less potent than 10 as antagonists, with IC(50) values of 14 and 16 microM, respectively, and no agonist activity was observed for these analogues. Thus, the ribose moiety is clearly not essential for recognition by the turkey P2Y(1) receptor, although a cyclic structure appears to be important for receptor activation, and the acyclic approach to the design of P2 receptor antagonists is valid.
P2Y(1)受体可被二磷酸腺苷激活，存在于内皮细胞、平滑肌、上皮细胞、肺、胰腺、血小板以及中枢神经系统中。借助分子模拟，我们设计出了作为该亚型选择性拮抗剂的核苷酸类似物。本研究检验了如下假设：核糖环的无环修饰对核苷类抗病毒药物（如更昔洛韦）非常成功，这种修饰也可推广至P2Y受体配体。具体而言，发现P2Y(1)受体的结合位点足以容纳用连接在腺嘌呤9位的无环脂肪族和芳香族链取代核糖基团。制备了三组具有不同侧链结构的腺嘌呤衍生物，每组都含有两个对称的磷酸或膦酸酯基团。无环衍生物在刺激火鸡红细胞膜中的磷脂酶C时表现出激动剂或拮抗剂的能力，从而证明了其生物活性。一种含有异戊基双磷酸酯部分的无环N(6)-甲基腺嘌呤衍生物，2-[2-(6-甲基氨基嘌呤-9-基)-乙基]-丙烷-1,3-双氧基(磷酸二铵)(10)，是P2Y(1)受体的完全拮抗剂，IC(50)值为1.60微摩。相应的2-氯衍生物(11)效力更强，IC(50)值为0.84微摩。9位乙烯基同系化为3至5个亚甲基单元或包含顺式或反式烯基会大大降低在P2Y(1)受体上的拮抗剂效力。含有二乙醇胺酰胺基团和芳基二(甲基膦酸酯)的类似物作为拮抗剂的效力均低于10，IC(50)值分别为14和16微摩，且未观察到这些类似物有激动剂活性。因此，尽管环状结构似乎对受体激活很重要，但核糖部分显然不是火鸡P2Y(1)受体识别所必需的，并且设计P2受体拮抗剂的无环方法是有效的。
