µ-conotoxin GIIIB

µ-conotoxin GIIIB is a 22-mer peptide originally isolated from the venom of the piscivorous marine snail Conus geographus. µ-conotoxin GIIIB adopts a compact structure consisting of a distorted 3₁₀-helix and a small ß-hairpin. µ-conotoxin GIIIB is stabilized by three disulphide bridges and is highly enriched in lysine and arginine residues, forming potential sites of interaction with Na channels. An unusual feature is the presence of three hydroxyproline residues. µ-conotoxin GIIIB is a useful probe to discriminate between neuronal and muscle sodium channels as it exhibits at least a 1000-fold specificity for muscle versus nerve sodium channels. µ-Conotoxin GIIIB selectively blocks Na_v1.4(µ1) voltage-dependent sodium channels, which are predominantly expressed in muscle, with an affinity close to 20 nM.µ-Conotoxin GIIIB appears to physically occlude the channel pore by binding on site I of the Na⁺ channel.

µ-conotoxin GIIIB technical information

AA sequence: Arg-Asp-Cys³-Cys⁴-Thr-Hyp-Hyp-Arg-Lys-Cys¹⁰-Lys-Asp-Arg-Arg-Cys¹⁵-Lys-Hyp-Met-Lys-Cys²⁰-Cys²¹-Ala-NH₂
Disulfide bonds: Cys³-Cys¹⁵, Cys⁴-Cys²⁰ and Cys¹⁰-Cys²¹
Length (aa): 22
Formula: C₁₀₁H₁₇₅N₃₉O₃₀S₇
Molecular Weight: 2640.26 Da
Appearance: White lyophilized solid
Solubility: water and saline buffer
CAS number:
Source: Synthetic
Purity rate: > 97 %