Structure-activity relationship studies on cyclic RGD peptides utilizing novel alkene dipeptide isosteres

Area of Science:

• Medicinal Chemistry
• Peptide Chemistry
• Biochemistry

Background:

• Cyclic Arg-Gly-Asp (RGD) peptides are crucial for targeting integrins.
• Understanding structure-activity relationships (SAR) is key to developing potent integrin antagonists.
• The N-methyl group in valine residues can influence peptide conformation and bioactivity.

Purpose of the Study:

• To investigate the impact of a valine N-methyl group on the bioactivity of cyclic RGD peptides.
• To synthesize and evaluate novel dipeptide isosteres for SAR studies.
• To elucidate the conformational effects of structural modifications on integrin binding.

Main Methods:

• Synthesis of novel D-Phe-Val-type dipeptide isosteres with methyl-substituted olefins.
• Utilized solution- and solid-phase peptide synthesis to create cyclic RGD peptidomimetics.
• Evaluated alpha(V)beta(3) and alpha(IIb)beta(3) integrin antagonistic activities.
• Performed structural calculations using simulated annealing and NMR data.

Main Results:

• Successfully synthesized four novel isosteres and corresponding cyclic RGD peptidomimetics.
• Comparative evaluation of integrin antagonistic activities revealed structure-dependent effects.
• Structural analysis provided insights into the influence of the valine N-methyl group and D-phenylalanine carbonyl oxygen.

Conclusions:

• The valine N-methyl group significantly influences the bioactivity and integrin antagonism of cyclic RGD peptides.
• Novel dipeptide isosteres are valuable tools for SAR studies in integrin antagonist development.
• Conformational changes induced by structural modifications impact interactions with alpha(V)beta(3) and alpha(IIb)beta(3) integrins.