MODIFICATIONS OF POSITION-12 IN PARATHYROID-HORMONE AND PARATHYROID-HORMONE RELATED PROTEIN - TOWARD THE DESIGN OF HIGHLY POTENT ANTAGONISTS
MODIFICATIONS OF POSITION-12 IN PARATHYROID-HORMONE AND PARATHYROID-HORMONE RELATED PROTEIN - TOWARD THE DESIGN OF HIGHLY POTENT ANTAGONISTS
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DOI：
10.1021/bi00458a032
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发表时间：
1990-02-13
期刊：
影响因子：
2.9
通讯作者：
ROSENBLATT, M
中科院分区：
文献类型：
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作者：
CHOREV, M;GOLDMAN, ME;ROSENBLATT, M
在骨和肾测定中，甲状旁腺激素（PTH）、[Tyr 34]牛PTH（7-34）NH 2和甲状旁腺激素相关蛋白（PTHrP）、PTHrP（7-34）NH 2的截短N-末端片段抑制[Nle 8，18[125 I]碘-Tyr 34]-bPTH（1-34）NH 2结合和PTH刺激的腺苷酸环化酶。然而，这些肽的受体相互作用比它们的激动剂对应物弱2-3个数量级。为了产生具有增加的受体结合亲和力但缺乏激动剂样性质的拮抗剂，进行了结构-功能研究。在位置12的甘氨酸（存在于PTH的所有同系物和PTHrP中），其被预测在两种激素中参与β-反过来，通过取代构象报告基因，如D-或L-Ala、Pro和α-Ala，氨基异丁酸（Aib），在激动剂和拮抗剂类似物中。除了N-取代的氨基酸，这大大降低了效力，取代是耐受良好的，这表明该网站可以接受广泛的修改。为了增加受体亲合力，引入与螺旋二级结构相容的疏水残基。非天然氨基酸D-Trp、D-α-Trp的掺入萘基丙氨酸（D-α- Nal）或D-β- Nal转化为[Tyr 34]bPTH（7-34）NH 2或[Nle 8，18，Tyr 34]bPTH（7-34）NH 2产生比它们各自的7-34母体化合物活性高约10倍的拮抗剂。类似地，[D-Trp 12]PTHrP（7-34）NH 2的效力比未取代的肽高6倍，但保留了部分激动性质，尽管与PTHrP（7-34）NH 2类似，显著降低。拮抗增强效应是构型特异性的。这项研究提供了一个合理的方法设计更有效的拮抗剂的PTH和PTHrP的基础上引入疏水残基（以增加受体亲合力）到网站内的拮抗剂序列已被确定为容忍的结构操作。
Truncated N-terminal fragments of parathyroid hormone (PTH), [Tyr34]bovine PTH(7-34)NH2, and parathyroid hormone related protein (PTHrP), PTHrP(7-34)NH2, inhibit [Nle8,18[125I]iodo-Tyr34]-bPTH(1-34)NH2 binding and PTH-stimulated adenylate cyclase in bone and kidney assays. However, the receptor interactions of these peptides are 2-3 orders of magnitude weaker than those of their agonist counterparts. To produce an antagonist with increased receptor-binding affinity but lacking agonist-like properties, structure-function studies were undertaken. Glycine at position 12 (present in all homologues of PTH and in PTHrP), which is predicted in both hormones to participate in a .beta.-turn, was examined by substituting conformational reporters, such as D- or L-Ala, Pro, and .alpha.-aminoisobutyric acid (Aib), in both agonist and antagonist analogues. Except for N-substituted amino acids, which substantially diminished potency, substitutions were well tolerated, indicating that this site can accept a wide latitude of modifications. To augment receptor avidity, hydrophobic residues compatible with helical secondary structure were introduced. Incorporation of the nonnatural amino acids D-Trp, D-.alpha.-naphthylalanine (D-.alpha.-Nal), or D-.beta.-Nal into either [Tyr34]bPTH(7-34)NH2 or [Nle8,18, Tyr34]bPTH(7-34)NH2 resulted in antagonists that were about 10-fold more active than their respective 7-34 parent compound. Similarly, [D-Trp12]PTHrP(7-34)NH2 was 6 times more potent than the unsubstituted peptide but retained partial agonistic properties, although markedly reduced, similar to PTHrP(7-34)NH2. The antagonistic potentiating effect was configurationally specific. This study provides the basis for a rational approach toward the design of more potent antagonists of both PTH and PTHrP based on the introduction of hydrophobic residues (to increase receptor avidity) into sites within the antagonist sequence which have been established to be tolerant of structural manipulation.