Lipopeptide conjugates: Biomolecular building blocks for receptor activating membrane-mimetic structures

A simple method for the derivatization of phospholipid subunits with short peptide sequences is presented. Amphiphilic conjugates of distearoylphosphatidylethanolamine (DSPE) and the minimal human thrombin-receptor peptide agonist SFLLRN were synthesized via coupling of the bromoacetyl derivative of DSPE (PEBr) with a thiol-terminated decapeptide of SFLLRN. Bromoderivatization of DSPE was performed by condensation of bromoacetic acid and DSPE, with an overall yield of 40%. Coupling of PEBr and the unprotected thiol-terminated decapeptide was performed in chloroform/ methanol/water in the presence of triethylamine and afforded 25.5% of the lipopeptide. The compound was characterized by TLC, H-1-NMR (600 MHz) and mass spectrometry. Lipopeptide bioactivity was confirmed by a platelet aggregation assay. The EC(50) of the all-L amino acid lipopeptide was 38 +/- 3 mu M. The all-D conjugate was inactive. Model receptor-activating systems, including well-ordered assemblies of amphiphilic phospholipid-peptide conjugates, represent the first step in the construction of bioactive surfaces for tissue engineering based on a membrane-mimetic approach.