N-Terminal Alkylation of Proteins with Triazole-4-carbaldehyde for Targeted Liposome Engineering

A platform method to associate native proteins and peptides onto a liposome membrane using site-specific N-terminal alkylation based on 1H-1,2,3-triazole-4-carbaldehyde (TA4C) is developed. The TA4C reagent reacts with the N-terminal -amino group of native proteins under mild aqueous conditions in a single step, without genetic engineering or protecting group strategies. Equipping TA4C with hexyl and nonyl chains provides a direct handle for tuning the association between the protein and membrane. N-terminal alkylation of green fluorescent protein (GFP) as a model proceeds in high yield (93% for the hexyl group and 70% for the nonyl group), and tethering the N-terminal alkyl group on GFP efficiently associates the protein with the liposomal membrane, as confirmed by confocal laser scanning microscopy and dynamic light scattering. We extended this strategy to an investigation of the GE11 peptide, a ligand for the epidermal growth factor receptor (EGFR). The liposome immobilized with GE11 peptide possessing an N-terminal alkyl group enables active targeting with EGFR-overexpressing A431 cells. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=80 SRC="FIGDIR/small/742023v1_ufig1.gif" ALT="Figure 1"> View larger version (20K): org.highwire.dtl.DTLVardef@1f4095org.highwire.dtl.DTLVardef@1c91509org.highwire.dtl.DTLVardef@841647org.highwire.dtl.DTLVardef@1d2909b_HPS_FORMAT_FIGEXP M_FIG C_FIG