Acid boosts a scorpion’s sting | August 7, 2017 Issue - Vol. 95 Issue 32 | Chemical & Engineering News
Volume 95 Issue 32 | p. 8 | Concentrates
Issue Date: August 7, 2017

Acid boosts a scorpion’s sting

The low pH of an East Asian scorpion’s venom helps one of its peptide toxins cause more pain
Department: Science & Technology
News Channels: Biological SCENE, Analytical SCENE
Keywords: biochemistry, venom, scorpion, pH, peptide
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The venom of the East Asian Buthidae scorpion Mesobuthus martensii uses low pH and a peptide to cause terrible pain in victims.
Credit: Shilong Yang
Photo of a scorpion (Mesobuthus martensii)
 
The venom of the East Asian Buthidae scorpion Mesobuthus martensii uses low pH and a peptide to cause terrible pain in victims.
Credit: Shilong Yang
[+]Enlarge
The scorpion peptide BmP01 is composed of a short α-helix and two β-strands cross-linked by three pairs of disulfide bonds and targets the pain receptor TRPV1.
Credit: Sci. Adv./AAAS
Image of the structure of a scorpion venom peptide.
 
The scorpion peptide BmP01 is composed of a short α-helix and two β-strands cross-linked by three pairs of disulfide bonds and targets the pain receptor TRPV1.
Credit: Sci. Adv./AAAS

The sting of an East Asian Buthidae scorpion causes excruciating pain thanks to more than 100 peptide toxins in its venom. In particular, the 29-amino acid peptide, BmP01, targets one of the most famous pain receptors in mammals, the ion channel called TRPV1, which is better known for being the receptor for capsaicin, the chemical responsible for hot chilies’ burn. But researchers have long puzzled over this conundrum: The concentration of BmP01 required to successfully hit TRPV1 is in the micromolar range, much higher than the levels of the peptide in the scorpion’s venom. So how does the peptide cause so much pain in victims? A team led by Jie Zheng of the University of California, Davis, and Ren Lai of the Chinese Academy of Sciences has an answer. The team reports that in addition to BmP01, protons in scorpions’ acidic venom also help activate TRPV1 (Sci. Adv. 2017, DOI: 10.1126/sciadv.1700810). The researchers note that “BmP01 binds to one of the two proton-binding sites on TRPV1 and, together with a proton, uses a one-two punch approach to strongly activate the nociceptive channel.”

 
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