Identification of Arginine Analogues as Antagonists and Agonists for the Melanocortin-4 Receptor
作者:Dai Nozawa、Taketoshi Okubo、Shigeyuki Chaki、Shigeru Okuyama、Atsuro Nakazato
DOI:10.1248/cpb.55.1232
日期:——
In the present study, conducted to explore potent and small molecular melanocortin-4 (MC4) receptor ligands, we found that tripeptide 3a, containing a D-Phe-Arg-2-Nal (Nal; naphthylalanine) sequence, exhibited a moderate affinity for the MC4 receptor. Structural optimization led to the identification of a compound with a high affinity for the MC4 receptor, namely, tripeptide 3e, which showed a 70-fold higher affinity for the MC4 receptor than the lead compound 3a. Moreover, in an effort to further reduce the peptidic characters of tripeptide 3e, we found that dipeptide 3g exhibited a relatively high affinity for the MC4 receptor. Furthermore, in these analogues, the substituted position (1′ vs. 2′) of the naphthyl ring of Nal residue at position 7 was found to be important for the differentiation of agonist and antagonist activity. The synthesis and structure–activity relationships of the arginine analogues as MC4 receptor ligands were described in this paper.
在本研究中,为了探索有效的小分子黑皮质素-4 (MC4) 受体配体,我们发现三肽 3a,含有 D-Phe-Arg-2-Nal(Nal;萘丙氨酸)序列,对 MC4 受体表现出中等亲和力。结构优化导致鉴定出对 MC4 受体具有高亲和力的化合物,即三肽 3e,其对 MC4 受体的亲和力比先导化合物 3a 高 70 倍。此外,为了进一步降低三肽3e的肽特性,我们发现二肽3g对MC4受体表现出相对较高的亲和力。此外,在这些类似物中,发现第 7 位 Nal 残基萘基环的取代位置(1' 与 2')对于区分激动剂和拮抗剂活性很重要。本文描述了作为 MC4 受体配体的精氨酸类似物的合成及其构效关系。