Direct evidence of edge-to-face CH/π interaction for PAR-1 thrombin receptor activation
Direct evidence of edge-to-face CH/π interaction for PAR-1 thrombin receptor activation
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DOI：
10.1016/j.bmc.2021.116498
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发表时间：
2021-11-15
影响因子：
3.5
通讯作者：
Shimohigashi, Yasuyuki
中科院分区：
文献类型：
--
作者：
Asai, Daisuke;Inoue, Naoko;Shimohigashi, Yasuyuki
七肽SFLLRNP是蛋白酶激活受体1（PAR - 1）的一种受体连接配体，其第2位的苯丙氨酸对人血小板聚集至关重要。为了验证苯丙氨酸苯基在受体激活中的结构要素，我们合成了一整套S/苯丙氨酸/LLRNP肽，包含不同系列的氟苯丙氨酸异构体（F - n）苯丙氨酸，其中n = 1、2、3和5。强烈表明苯丙氨酸 - 2 - 苯基参与了与受体芳香基团的边对面CH/π相互作用。在本研究中，为了明确证明这种受体相互作用，我们合成了另一系列含有（F - 4）苯丙氨酸异构体的肽类似物，每个异构体的苯基在邻位、间位或对位只有一个氢原子。当对这些肽的血小板聚集活性进行测定时，S/（2,3,4,6 - F - 4）苯丙氨酸/LLRNP和S/（2,3,4,5 - F - 4）苯丙氨酸/LLRNP表现出显著的活性（分别为天然肽活性强度的34%和6%），而S/（2,3,5,6 - F - 4）苯丙氨酸/LLRNP则完全无活性。结果表明，在邻位和间位而非对位，苯 - 氢原子是激活受体的CH/π相互作用所必需的。这些结果为苯丙氨酸的分子识别特性提供了决定性证据，其苯 - 氢原子直接参与了与受体芳香π平面的相互作用。
Heptapeptide SFLLRNP is a receptor-tethered ligand of protease-activated receptor 1 (PAR-1), and its Phe at position 2 is essential for the aggregation of human platelets. To validate the structural elements of the Phephenyl group in receptor activation, we have synthesized a complete set of S/Phe/LLRNP peptides comprising different series of fluorophenylalanine isomers (F-n)Phe, where n = 1, 2, 3, and 5. Phe-2-phenyl was strongly suggested to be involved in the edge-to-face CH/pi interaction with the receptor aromatic group. In the present study, to prove this receptor interaction definitively, we synthesized another series of peptide analogs containing (F-4)Phe-isomers, with the phenyl group of each isomer possessing only one hydrogen atom at the ortho, meta, or para position. When the peptides were assayed for their platelet aggregation activity, S/(2,3,4,6-F-4)Phe/LLRNP and S/(2,3,4,5-F-4)Phe/LLRNP exhibited noticeable activity (34% and 6% intensities of the native peptide, respectively), whereas S/(2,3,5,6-F-4)Phe/LLRNP was completely inactive. The results indicated that, at the ortho and meta positions but not at the para position, benzene-hydrogen atoms are required for the CH/pi interaction to activate the receptor. The results provided a decisive evidence of the molecular recognition property of Phe, the phenyl benzene-hydrogen atom of which participates directly in the interaction with the receptor aromatic pi plane.