Peptide Synthesis

Linear peptides were synthesized by solid-phase peptide synthesis using an automatic peptide synthesizer (Symphony^®, Protein Technologies, Inc., Tucson, AZ) following standard Fmoc chemistry protocols. 2-Chlorotrityl chloride resin was used for [GGG] PVIIA[LPETGG], whereas rink amide resin was used for linear κ-PVIIA to achieve C-terminal amidation. κ-PVIIA with N-terminal acetylation was produced by treating the resin with 6% acetic acid/0.2 M DIPEA in DMF following completion of elongation of the peptide. Peptides were released from the resins using trifluoroacetic acid (TFA)/triisopropylsilane/water (95:2.5:2.5) at room temperature for 2 h. TFA was removed using a rotary evaporator, and peptides were precipitated with ice-cold diethyl ether, dissolved in 50% v/v acetonitrile (ACN) containing 0.05% v/v TFA and lyophilized. Peptides were purified using reversed-phase high performance liquid chromatography (RP-HPLC) and the mass was confirmed using mass spectrometry.