Gene construction, expression and functional testing of an inotropic peptide from the venom of the black scorpion Hottentotta judaicus

► Bj-IP, a new anti-insect depressant βNaScTx, was isolated from Hottentotta judaicus. ► The synthesis of this toxin gene was achieved by splicing by overlap extension PCR. ► Bj-IP was expressed in Escherichia coli and purified by NiNTA agarose and HPLC. ► Mass spectrometry confirmed the theoretical mass of the recombinant toxin (6608 Da). ► After refolding, Bj-IP increased myocyte contraction and accelerated relaxation.