Nakamoto C, Behar V, Chin K R, Adams A E, Suva L J, Rosenblatt M, Chorev M
Division of Bone and Mineral Metabolism, Harvard-Thorndike Laboratories, Beth Israel Hospital, Boston, Massachusetts, USA.
Biochemistry. 1995 Aug 22;34(33):10546-52. doi: 10.1021/bi00033a029.
Parathyroid hormone (PTH) regulates calcium and phosphate metabolism through a G-protein-coupled receptor which is shared with PTH-related protein (PTHrP). Therefore, structure-activity studies of PTH and PTHrP with their common receptor provide an unusual opportunity to examine the structural elements in the two hormones and their common receptor which are involved in the expression of biological activity. Our approach to studying the nature of the bimolecular interface between hormone and receptor is to use a series of specially designed photoreactive benzophenone- (BP-) containing PTH analogs in "photoaffinity scanning" of the PTH/PTHrP receptor. In this report we describe a series of BP-containing agonists and antagonists which have been synthesized by solid-phase methodology and characterized physiocochemically and biologically. Each of the 12 analogs contains a single BP moiety at a different defined position. Examples of BP-containing agonists prepared and studied in human osteogenic sarcoma Saos-2/B-10 cells are [Nle8,18,Lys13(epsilon-pBZ2),L-2-Nal23,Tyr34]bPTH(1-34 )NH2(K13)(Kb = 13 nM; Km = 2.7 nM) and [Nle8,18,L-Bpa23,Tyr34[bPTH(1-34)NH2(L-Bpa23) (Kb = 42 nM; Km = 8.5 nM). Another BP-containing analog, [Nle8,18,D-2-Nal12,Lys13(epsilon-pBZ2),L-2-Nal23 ,Tyr34]bPTH(7-34)NH2, was a potent antagonist (Kb = 95 nM; Ki = 72 nM). The amino acids substituted by residues carrying the BP moiety span the biologically active domain of the hormone (Phe7, Gly12, Lys13, Trp23, and Lys26). Analysis of photo-cross-linked conjugates of PTH/PTHrP receptor with BP-containing PTH analogs should help to identify the "contact points" between ligand and receptor.
甲状旁腺激素（PTH）通过与甲状旁腺激素相关蛋白（PTHrP）共用的G蛋白偶联受体来调节钙和磷的代谢。因此，对PTH和PTHrP与其共同受体进行构效关系研究，为考察这两种激素及其共同受体中参与生物活性表达的结构元件提供了一个难得的机会。我们研究激素与受体之间双分子界面性质的方法是，在PTH/PTHrP受体的“光亲和扫描”中使用一系列经过特殊设计的含光反应性二苯甲酮（BP）的PTH类似物。在本报告中，我们描述了一系列通过固相方法合成的含BP的激动剂和拮抗剂，并对其进行了物理化学和生物学表征。这12种类似物中的每一种在不同的指定位置都含有一个单一的BP部分。在人骨肉瘤Saos-2/B-10细胞中制备并研究的含BP激动剂的例子有[Nle8,18,Lys13(ε-pBZ2),L-2-Nal23,Tyr34]bPTH(1-34)NH2(K13)(Kb = 13 nM; Km = 2.7 nM)和[Nle8,18,L-Bpa23,Tyr34[bPTH(1-34)NH2(L-Bpa23)(Kb = 42 nM; Km = 8.5 nM)。另一种含BP的类似物[Nle8,18,D-2-Nal12,Lys13(ε-pBZ2),L-2-Nal23,Tyr34]bPTH(7-34)NH2是一种强效拮抗剂（Kb = 95 nM; Ki = 72 nM）。被携带BP部分的残基取代的氨基酸跨越了激素的生物活性结构域（Phe7、Gly12、Lys13、Trp23和Lys26）。对PTH/PTHrP受体与含BP的PTH类似物的光交联缀合物的分析，应有助于确定配体与受体之间的“接触点”。
