Structural and conformational requirements for high-affinity binding to the SH2 domain of Grb2
Structural and conformational requirements for high-affinity binding to the SH2 domain of Grb2
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DOI：
10.1021/jm9811007
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发表时间：
1999-03-25
影响因子：
7.3
通讯作者：
Bair, KW
中科院分区：
文献类型：
--
作者：
Ettmayer, P;France, D;Bair, KW
继早期对胱氨酸桥肽的研究之后，合成了含有不可还原的胱氨酸模拟物的环状磷酸肽，其对生长因子受体结合蛋白 (Grb2) 的 Src 同源 (SH2) 结构域表现出高亲和力和特异性。用 D-α-乙酰基硫赖氨酸或 D-α-赖氨酸替换环状七肽环 (CY*VNVPC) 中的胱氨酸，得到环(Y*VNVP(D-α-乙酰基-thiaK)) (22) 和环(Y*VNVP(D-α-乙酰基-K)) (30)，其结合能力比对照肽 KPFY*VNVEF 提高了 10 倍(1). NMR 波谱和分子建模实验表明，以 Y*VNV 为中心的 β 转角构象对于高亲和力结合至关重要。 X射线结构分析表明，线性肽1和环状化合物21采用相似的β-转角构象结合方式。我们的数据证实了 Grb2 SH2 结构域的配体结合位点的独特结构要求。此外，我们的环状内酰胺的效力可以通过三个分子内氢键（一个由 H2O 分子介导）稳定 β 转角构象来解释。这些稳定且易于获取的环肽可以作为评估磷酸酪氨酸替代物和进一步化学精制的模板。
Following earlier work on cystine-bridged peptides, cyclic phosphopeptides containing nonreducible mimics of cystine were synthesized that show high affinity and specificity toward the Src homology (SH2) domain of the growth factor receptor-binding protein (Grb2). Replacement of the cystine in the cyclic heptapeptide cyclo(CY*VNVPC) by D-alpha-acetylthialysine or D-alpha-lysine gave cyclo(Y*VNVP(D-alpha-acetyl-thiaK)) (22) and cyclo(Y*VNVP(D-alpha-acetyl-K)) (30), which showed improved binding 10-fold relative to that of the control peptide KPFY*VNVEF (1). NMR spectroscopy and molecular modeling experiments indicate that a beta-turn conformation centered around Y*VNV is essential for high-affinity binding. X-ray structure analyses show that the linear peptide 1 and the cyclic compound 21 adopt a similar binding mode with a beta-turn conformation. Our data confirm the unique structural requirements of the ligand binding site of the SH2 domain of Grb2. Moreover, the potency of our cyclic lactams can be explained by the stabilization of the beta-turn conformation by three intramolecular hydrogen bonds (one mediated by an H2O molecule). These stable and easily accessible cyclic peptides can serve as templates for the evaluation of phosphotyrosine surrogates and further chemical elaboration.