Recombinant Production and Structure-Function Study of the Ts1 Toxin from the Brazilian Scorpion Tityus serrulatus.

An effective bacterial system for the production of β-toxin Ts1, the main component of the Brazilian scorpion Tityus serrulatus venom, was developed. Recombinant toxin and its ¹⁵ N-labeled analogue were obtained via direct expression of synthetic gene in Escherichia coli with subsequent folding from the inclusion bodies. According to NMR spectroscopy data, the recombinant toxin is structured in an aqueous solution and contains a significant fraction of β-structure. The formation of a stable disulfide-bond isomer of Ts1, having a disordered structure, has also been observed during folding. Recombinant Ts1 blocks Na ⁺ current through Na _V 1.5 channels without affecting the processes of activation and inactivation. At the same time, the effect upon Na _V 1.4 channels is associated with a shift of the activation curve towards more negative membrane potentials.