Synthesis, conformational properties, and antibody recognition of peptides containing .beta.-turn mimetics based on .alpha.-alkylproline derivatives
摘要:
Peptide recognition by monoclonal antibodies may provide a useful model for drug development, in particular to test the effects of conformational restriction on ligand binding. We have tested the influence of novel peptide mimetics upon conformation and binding affinity for the case of monoclonal antibodies raised to a peptide antigen which displays a preference for a beta-turn conformation in aqueous solution. Two monoclonals were isolated that recognized the peptide Ac-Tyr-Pro-Tyr-Asp-Val-Pro-Asp-Tyr-Ala specifically at the beta-turn formed by Tyr-Pro-Tyr-Asp. Peptide analogues were then synthesized containing mimetics designed to stabilize this conformation. One, analogue (3), contained a spirocyclic gamma-lactam bridge between the alpha-position of proline-2 and the N atom of tyrosine-3, while another (2) contained (S)-alpha-methylproline at position 2. NMR spectroscopy and molecular modeling suggest that both analogues adopt reverse-turn conformations stabilized relative to that in the native sequence. For the (S)-alpha-methylproline analogue binding to both monoclonal antibodies was substantially improved, compared with the native antigen, whereas the gamma-lactam analogue (3) was not recognized by either antibody. Quantitative equilibrium ultrafiltration binding assays showed that the affinities of the (S)-alpha-methylproline analogue (2) for the two antibodies were improved over those measured with the native antigen by -2.3 and -0.65 kcal/mol. The origins of these free energy differences cannot be explained wholly on the basis of presumed extra hydrophobic contacts between the new methyl substituent and the antigen binding sites. We propose that the increased conformational stability of the analogue plays a decisive role, implying that the reverse turn detected in the native antigen, possibly a type-I turn, is important for recognition by the two antibodies.
C 2 -Symmetrical hemiaminal ethers and diamines with a piperazine core were synthesized starting from Seebach’s oxazolidinone. The new methodology is based on the dimerization of α-amino aldehydes to bicyclic bishemiaminal ethers, followed by reduction to the corresponding diamines. Several enantiopure piperazine derivatives bearing either methyl or bulky groups including isopropyl and aryl at the
Novel peptides which can act to inhibit renin and can have utility in the diagnosis and control of renin-dependent hypertension, and intermediates in the preparation of both the new and known renin-inhibiting peptides.
可抑制肾素并可用于诊断和控制肾素依赖性高血压的新型肽,以及制备新型和已知肾素抑制肽的中间体。
Renin-inhibiting peptides
申请人:THE UPJOHN COMPANY
公开号:EP0486478A2
公开(公告)日:1992-05-20
A renin inhibitory peptide comprising a N-alkylhistidine moiety at the position corresponding to the 9-position of the human renin substrate.
An improved method of oxazolidinone hydrolysis in the asymmetric synthesis of α-alkylprolines
作者:Michael J. Genin、Paul W. Baures、Rodney L. Johnson
DOI:10.1016/s0040-4039(00)73294-1
日期:1994.7
An improvement in Seebach's method for the synthesis of alpha-alkylprolines is reported wherein the hydrolysis of the chiral oxazolidinone 2 is performed on a suspension of silica gel in MeOH/H2O. Following hydrolysis, the pure alpha-alkylproline can he obtained by filtration thereby avoiding a tedious ion exchange purification.