The role of Ser54 in the antinociceptive activity of BmK9, a neurotoxin from the scorpion Buthus martensii Karsch

► Ser54 is important for the antinociceptive activity of scorpion neurotoxin BmK9. ► Ser54 exerts its effect by means of a side-chain hydrogen bond. ► Our results show that Ser54 plays a functional role in the antinociceptive activity.