La1 is a 73-residue peptide containing four disulfide bonds. It has been isolated from scorpion venom, but its biological function remains unknown.
In this study, the researchers developed a method for the chemical synthesis of La1 in milligram quantities, using the native chemical ligation (NCL) strategy, in which three peptide segments of less than 40 residues were sequentially ligated. Each peptide thioester necessary for NCL was synthesized using an aromatic N-acylurea approach with Fmoc-SPPS. Linear La1 obtained by sequential NCL was then oxidized to form the four disulfide bonds using a dialysis method, which allowed the correct folding of La1. Furthermore, the disulfide bonding pattern of La1 was determined by MS and MS/MS analysis. La1 synthesized by the method established in this study will be useful for future investigation of its biological roles in the venom.
The three peptide fragments were synthesized using microwave-assisted Fmoc-SPPS on a Biotage® Initiator+ microwave synthesizer.
Disulfide bonding pattern of peptide La1.
Nagao, J., Miyashita, M., Nakagawa, Y., and Miyagawa, H. (2015), Chemical synthesis of La1 isolated from the venom of the scorpion Liocheles australasiae and determination of its disulfide bonding pattern. J. Pept. Sci., doi: 10.1002/psc.2778
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