MeuTXK beta 1, a scorpion venom-derived two-domain potassium channel toxin-like peptide with cytolytic activity
Zhu, Shunyi × Gao, Bin Aumelas, Andre del Carmen Rodriguez, Maria Lanz-Mendoza, Humberto Peigneur, Steve Diego-Garcia, Elia Martin-Eauclaire, Marie-France Tytgat, Jan Possani, Lourival D #
Biochimica et Biophysica Acta. Proteins and Proteomics vol:1804 issue:4 pages:872-883
Recent studies have demonstrated that scorpion venom contains unique two-domain peptides with the peculiarity of possessing different functions, i.e. neurotoxic and cytolytic activities. Here we report systematic characterization of a new two-domain peptide (named MeuTXK beta 1) belonging to the TsTXK beta molecular subfamily from the scorpion Mesobuthus eupeus by molecular cloning, biochemical purification, recombinant expression, functional assays, CD and NMR studies. Its full-length bioactive form as well as 1-21 and 22-72 fragments (named N(1-21) and C(22-72), respectively) was produced in Escherichia coli by an on-column refolding approach. Recombinant peptide (rMeuTXK beta 1) exhibited a low affinity for K+ channels and cytolytic effects against bacteria and several eukaryotic cells. N(1-21) was found to preserve anti-Plasmodium activity in contrast to haemolytic activity, whereas C(22-72) retains these two activities. Circular dichroism analysis demonstrates that rMeuTXK beta 1 presents a typical scorpion toxin scaffold in water and its alpha-helical content largely increases in a membrane-mimicking environment, consistent with the NMR structure of N(1-21) and an ab initio structure model of MeuTXK beta 1 predicted using I-TASSER algorithm. Our structural and functional data clearly indicate an evolutionary link between TsTXK beta-related peptides and antiparasitic scorpines which both comprise the beta SPN (beta-KTxs and scorpines) family. (C) 2009 Elsevier B.V. All rights reserved.