Direct evidence of edge-to-face CH/π interaction for PAR-1 thrombin receptor activation. (1st December 2021)

• Record Type: Journal Article
• Authors: Asai, Daisuke; Inoue, Naoko; Sugiyama, Makiko; Fujita, Tsugumi; Matsuyama, Yutaka; Liu, Xiaohui; Matsushima, Ayami; Nose, Takeru; Costa, Tommaso; Shimohigashi, Yasuyuki
• Is Part Of: Bioorganic & medicinal chemistry. Volume 51(2021)
• Publication Date: 2021-12-01
• Subjects: CH/π interaction -- Fluorophenylalanine -- Phenylalanine -- Thrombin receptor; Boc t.-butoxycarbonyl -- Cha cyclohexylalanine -- (Fn)Phe fluoro-phenylalanines -- HATU 1-[bis(dimethylamino)methylene]-1H-1, 2, 3-triazolo[4, 5-b] pyridinium 3-oxide hexafluorophosphate -- HOAt 1-hydroxy-7-azabenzotriazole -- MALDI­ TOF matrix-assisted laser desorption ionization time of flight -- MBHA para-methylbenzhydrylamine -- (F5)Phe or (2, 3, 4, 5, 6-F5)Phe pentafluorophenylalanine -- PPP platelet-poor plasma -- RP-HPLC reversed-phase high performance liquid chromatography -- S/Phe/LLRNP or SFLLRNP Ser-Phe-Leu-Leu-Arg-Asn-Pro -- TFA trifluoroacetic acid -- PRP platelet-rich plasma; Bioorganic chemistry -- Periodicals; Pharmaceutical chemistry -- Periodicals; Biochemistry -- Periodicals; Chemistry, Clinical -- Periodicals; Chemistry, Organic -- Periodicals; Chimie bio-organique -- Périodiques; Chimie pharmaceutique -- Périodiques; 615.19
• DOI: 10.1016/j.bmc.2021.116498
• Languages: English
• ISSNs: 0968-0896

Abstract

Graphical abstract: Highlights: Three structural isomers of l -tetrafluorophenylalanine (F4 )Phe were synthesized. Each isomer has only one H atom at the ortho, meta, or para position of Phe-phenyl. Isomers were incorporated into the PAR-1 receptor–tethered ligand S/Phe/LLRNP. Two of isomers exhibited noticeable activity in the platelet aggregation assay. Phe-phenyl benzene-H atoms were found necessary to activate PAR-1 receptor. Abstract: 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 Phe-phenyl group in receptor activation, we have synthesized a complete set of S/Phe/LLRNP peptides comprising different series of fluorophenylalanine isomers (Fn )Phe, where n = 1, 2, 3, and 5. Phe-2-phenyl was strongly suggested to be involved in the edge -to- face CH/π interaction with the receptor aromatic group. In the present study, to prove this receptor interaction definitively, we synthesized another series of peptide analogs containing (F4 )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-F4 )Phe/LLRNP and S/(2, 3, 4, 5-F4 )Phe/LLRNP exhibited noticeable activity (34% and 6% intensities of the native peptide, respectively), whereas S/(2, 3, 5, 6-F4 )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/π 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 π plane.