Investigation of the binding determinants of phosphopeptides targeted to the Src homology 2 domain of the signal transducer and activator of transcription 3. Development of a high-affinity peptide inhibitor
Investigation of the binding determinants of phosphopeptides targeted to the Src homology 2 domain of the signal transducer and activator of transcription 3. Development of a high-affinity peptide inhibitor
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DOI：
10.1021/jm050513m
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发表时间：
2005-10-20
影响因子：
7.3
通讯作者：
McMurray, JS
中科院分区：
文献类型：
--
作者：
Coleman, DR;Ren, ZY;McMurray, JS
信号转导器和转录激活剂 3 (Stat3) 是一种胞质转录因子，它将来自细胞膜的信号直接与细胞核联系起来，在细胞核中它与其他蛋白质复合，启动抗凋亡和细胞周期基因的转录，例如 Bcl-x(L) 和细胞周期蛋白 D1。在正常细胞中，Stat3 转导来自细胞因子（例如 IL-6）和生长因子（例如表皮生长因子）的信号。 Stat3 在许多人类肿瘤中被组成性激活。反义和显性失活基因传递导致细胞凋亡和细胞生长减少，因此该蛋白是抗癌药物设计的一个有吸引力的靶标。作为我们设计 Src 同源 2 (SH2) 定向 Stat3 拟肽抑制剂研究的一部分，在本文中，我们描述了结构-活性关系研究，该研究提供了有关 Stat3 二聚化和 DNA 结合的高亲和力磷酸肽抑制剂 Ac-Tyr(PO3H2)-Leu-Pro-Gln-Thr-Val-NH2、肽的肽-蛋白质相互作用性质的信息。 1. SH2结构域上有一个疏水表面，可以容纳N端的亲脂基团。在测试的氨基酸中，亮氨酸在 pY+1 处提供了最高的亲和力，其主链 NH 与 Stat3（推测为 Ser636）形成氢键。 cis-3,4-Methanoproline 是 pY+2 处的最佳主链约束。 Gln 的侧链酰胺质子是高亲和力相互作用所必需的。 C 末端二肽 Thr-Val 可以被大小从甲基到苄基的基团替换。我们合成了一种包含基团的磷酸肽，该基团在每个位置上提供了亲和力的增加。因此，氢化肉桂酰基-Tyr(PO3H2)-Leu-cis-3,4-methanoPro-Gln-NHBn, 50 是亲和力最高的肽，在荧光偏振测定中，肽 1 的 IC50 为 125 nM，而肽 1 为 290 nM。
Signal transducer and activator of transcription 3 (Stat3) is a cytosolic transcription factor that relates signals from the cell membrane directly to the nucleus where it, in complex with other proteins, initiates the transcription of antiapoptotic and cell cycling genes, e.g., Bcl-x(L) and cyclin D1. In normal cells Stat3 transduces signals from cytokines such as IL-6 and growth factors such as the epidermal growth factor. Stat3 is constitutively activated in a number of human tumors. Antisense and dominant negative gene delivery result in apoptosis and reduced cell growth, thus this protein is an attractive target for anticancer drug design. As part of our research on the design of Src homology 2 (SH2) directed peptidomimetic inhibitors of Stat3, in this paper we describe structure-activity relationship studies that provide information on the nature of peptide-protein interactions of a high-affinity phosphopeptide inhibitor of Stat3 dimerization and DNA binding, Ac-Tyr(PO3H2)-Leu-Pro-Gln-Thr-Val-NH2, peptide 1. There is a hydrophobic surface on the SH2 domain that can accommodate lipophilic groups on the N-terminus. Of the amino acids tested, leucine provided the highest affinity at pY+1 and its main chain NH is involved with a hydrogen bond with Stat3, presumably Ser636. cis-3,4-Methanoproline is optimal as a backbone constraint at pY+2. The side chain amide protons of Gln are required for high-affinity interactions. The C-terminal dipeptide, Thr-Val, can be replaced with groups ranging in size from methyl to benzyl. We synthesized a phosphopeptide incorporating groups that provided increases in affinity at each position. Thus, hydrocinnamoyl-Tyr(PO3H2)-Leu-cis-3,4-methanoPro-Gln-NHBn, 50, was the highest affinity peptide, exhibiting an IC50 of 125 nM versus 290 nM for peptide 1 in a fluorescence polarization assay.