The role of the arginine residue in site RC for the analgesic activity of the recombinant Chinese scorpion Buthus martensii Karsch, BmK AGP-SYPU1

Abstract Scorpion venom is composed of a large number of bioactive peptides which display important pharmacological activities. In this study we have carried out a study of the functional role of the arginine residue at position 58 in the site RC comprising the reverse turn (8–12) and C-terminal residues 58–64. A polymerase chain reaction was used to substitute this arginine residue with a single amino acid such as alanine, glycine and lysine. The mutants were expressed in soluble form in E. coli , and purified by affinity chromatography. After target peptide purity identification, the recombinant peptides underwent a circular dichroism analysis and a study of their analgesic activity in mice. The results indicated that a single residue modification can affect the pharmacological activity. Our efforts establish a sound basis for further study of the structure-function determinants of the analgesic effect.