Gel-phase peptide synthesis on a new high-capacity tetraethyleneglycol diacrylate-crosslinked polystyrene support: synthesis of pardaxin 16-33

Abstract

An insoluble but highly solvating copolymer composed of tetraethyleneglycol diacrylate (TTEGDA)-crosslinked polystyrene has been prepared in beaded form by free-radical suspension polymerization of the monomers and employed as a new solid support for gel-phase peptide synthesis. This new polymer support has comparable physical and mechanical properties as that of the divinylbenzene (DVB)-crosslinked polystyrene support permitting identical manipulation such as shaking and filtration when used as a support for solid-phase peptide synthesis. This polystyrene-TTEGDA crosslinked polystyrene resin undergoes much more effective swelling and solvation than DVB-crosslinked polystyrene in a range of solvents with widely varying polarity which are commonly employed synthesis. The resin can be easily chloromethylated under controlled conditions to prepare resins of varying capacity ranging from low (0.15 meq/g) to high capacity (3.5meq/g). A high capacity resin with 1.5 meq/g chlorine capacity was used for synthesis of hydrophilic C-terminal 18-residue peptide of pardaxin from Pardachirus Pavoninus. The peptide was cleaved from the polymeric support by trifluoroacetic acid at 37°C and purified by Fast Protein Liquid Chromatography (FPLC). The purified peptide was shown to be homogeneous by HPLC and the identity of the 18-residue peptide was confirmed by amino acid analysis. The free peptide possesses a disordered conformation as revealed by the CD measurement.