Lq2

Lq2 is a component of the venom of the scorpion Leiurus quinquestriatus. It blocks various potassium channels, among others the inward-rectifier potassium ion channel ROMK1.[1]


Alternative names

Lq2 is also known as Potassium channel toxin alpha-KTx 1.2, Charybdotoxin-2, ChTX-Lq2, ChTx-d, Toxin 18-2 or Lqh 18-2.

Etymology

The name Lq2 refers to the name of the animal species in which the toxin can be found.[2] Lq2 can be found in the scorpion Leiurus quinquestriatus (Lq).[3][4] Lq2 is structurally similar to Lq1, which had been found previously and which is also a potassium channel blocker.

Source

Lq2 is a component of the venom of the scorpion Leiurus quinquestriatus, known under various names, for example the deathstalker, the Israeli desert scorpion or the yellow scorpion.

Structure

Lq2 is a small peptide of 37 amino acids. Lq2 contains the classical scorpion toxin alpha-beta scaffold and is structurally similar to the neurotoxin Charybdotoxin (CTX).[5] Lq2 consists of an α-helix and a β-sheet, connected by an αβ3 loop containing disulfide bridges. The proteins three-dimensional structure has been reconstructed using nuclear magnetic resonance techniques.[5]

Target

Lq2 interacts with all three types of potassium channels:[6] the voltage-activated, the Ca2+- activated and the inward-rectifier potassium channels.[7] The unique trait of Lq2 is its high affinity for certain inward-rectifier potassium ion channels, especially the Renal Outer Medullary Potassium channel ROMK1. This ion channel contributes to the regulation of the resting membrane potential.

Mode of action

Since all potassium channels share the same ion conducting outer pore structure, Lq2 binds to all three potassium channel types. Lq2 interacts with the T-X-X-T-X-GT-X-X-T-X-GY/F-Gt K+-selective section within the pore-forming region (P-region) of the ROMK1 ion channel. It blocks the channel, binding in a 1:1 stoichiometric ratio with its β-sheet.[8]

Therapeutic use

Potential use of Lq2 is mainly in cardiovascular diseases.[3]

References

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.