Intrepicalcin

Intrepicalcin (ViCaTx1) is a short peptide toxin found in the venom of scorpion Vaejovis intrepidus. It is one of a group of short, basic peptides called , which bind to ryanodine receptors (RyRs) and thereby trigger calcium release from the sarcoplasmic reticulum.

Etymology[]

The name intrepicalcin is a combination of the species name of the organism that produces it (Vaejovis intrepidus) and the family name of short toxins that it belongs to ().

Source[]

Intrepicalcin is a toxin derived from the venom gland of the scorpion Vaejovis intrepidus ^[1]. This species belongs to the family of Vaejovidae in the order of Scorpiones.^[2] Vaejovis intrepidus is endemic to central Mexico.^[3]

Chemistry[]

Structure and family[]

Intrepicalcin (ViCaTx1) belongs to the scorpion calcin family. The structure of is specified by the Inhibitor Cystine Knot (ICK) motif. This folding motif is found in many toxins interacting with calcium channels in spiders and snails and distinguishes them from sodium, potassium and chloride channel toxins in scorpions. All calcins are composed of 33 amino acids, among which are 6 cysteines. These cysteines are highly conserved and form three disulfide bonds that are important for the ICK motif. In intrepicalcin and some other calcins, three of these cysteines are embedded in three