167612-97-7Relevant academic research and scientific papers
Differences in backbone structure between angiotensin II agonists and type I antagonists
Matsoukas,Agelis,Wahhab,Hondrelis,Panagiotopoulos,Yamdagni,Wu,Mavromoustakos,Maia,Ganter,Moore
, p. 4660 - 4669 (2007/10/02)
Type I angiotensin II antagonists with O-methyl-L-homoserine [HSer(γ- OMe)] and δ-methoxy-L-norvaline [Nva(δ-OMe)] at position 8 have been prepared by the solid-phase method, purified by reverse-phase HPLC, and bioassayed in the rat uterus, and their backbone conformational properties were investigated by nuclear Overhauser effect (NOE) spectroscopy. [Sar1,HSer-(γ-OMe)8]ANGII, [HSer(γ-OMe)8]ANGII, [Des1,HSer(γ- OMe)8]ANGII, [Sar1,Nva(δ-OMe)8]-ANGII, and [Des1,Nva(δ-OMe)8]ANGII had, respectively, the following antagonist activities, pA2: 7.6, 7.5, 1]ANGII with δ-hydroxy-L-norvaline [Nva(δ- OH)], δ-methoxy-L-norvaline [Nva(δ-OMe)], 4'-carboxyphenylalanine [Phe(4'- COOH)], and 4'-(trifluoromethyl)phenylalanine [Phe(4'-CF3)] at position 4 were also prepared by solid phase and bioassayed in the rat uterus. [Sar1,Nva(δ-OH)4]ANGII, [Aib1,Nva(δ-OMe)4]ANGII, [Sar1, DL-Phe(4'- COOH)4]ANGII, and [Sar1,DL-Phe(4'-CF3)4]ANGII had, respectively, agonist activities as follows: 4%, 1.5%, 3%, 8 in Sarilesin with the higher homologs HSer(γ-OMe) and Nva(δ-OMe) does not greatly alter the structural requirements necessary for expression of type I antagonist activity, while replacement of the tyrosine hydroxyl in [Sar1]ANGII by the carboxylate or the trifluoromethyl group abolishes activity, suggesting that the tyrosinate pharmacophore cannot be replaced by any negatively charged or electronegative group. Conformational investigation of the ANGII type I antagonists [HSer(γ- OMe)8]ANGII and [Sar1 Nva(δ-OMe)8]ANGII in DMSO by 1D-NOE spectroscopy revealed that the Tyr-Ile-His bend, a conformational property found in ANGII and [Sar1]ANGII (J. Biol. Chem. 1994, 269, 5303) is not present in type I antagonists, providing for the first time an important conformational difference between angiotensin II agonists and type I antagonists.
