MeuTXKbeta1, a scorpion venom-derived two-domain potassium channel toxin-like peptide with cytolytic activity.
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 MeuTXKbeta1) belonging to the TsTXKbeta 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 (rMeuTXKbeta1) 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 rMeuTXKbeta1 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 MeuTXKbeta1 predicted using I-TASSER algorithm. Our structural and functional data clearly indicate an evolutionary link between TsTXKbeta-related peptides and antiparasitic scorpines which both comprise the betaSPN (beta-KTxs and scorpines) family.
Zhu
Shunyi
S
Group of Animal Innate Immunity, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Chaoyang District, Beijing 100101, China. Zhusy@ioz.ac.cn
Gao
Bin
B
Aumelas
André
A
del Carmen Rodríguez
Maria
M
Lanz-Mendoza
Humberto
H
Peigneur
Steve
S
Diego-Garcia
Elia
E
Martin-Eauclaire
Marie-France
MF
Tytgat
Jan
J
Possani
Lourival D
LD
D000595:Amino Acid Sequence; D000818:Animals; D001419:Bacteria / Q000187:drug effects; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D006461:Hemolysis / Q000187:drug effects; D066298:In Vitro Techniques; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000633:toxicity*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000633:toxicity; D010962:Plasmodium berghei / Q000187:drug effects; D015221:Potassium Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000633:toxicity; D012604:Scorpion Venoms / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000633:toxicity*; D012605:Scorpions / Q000737:chemistry / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013574:Synaptosomes / Q000378:metabolism
D017931:DNA Primers; D009498:Neurotoxins; D010446:Peptide Fragments; D015221:Potassium Channels; D011994:Recombinant Proteins; D012604:Scorpion Venoms