µ-Conotoxin GIIIB

μ-Conotoxin GIIIB is a 22-residue polypeptide that can be isolated from the venom of piscivorous cone snail Conus geographus. μ-Conotoxin GIIIB is a NaV1.4 channel inhibitor. μ-Conotoxin GIIIB blocks muscle cell's contraction[1][2][3].

[O=C1[C@]2(N(C(=O)[C@]([C@@H](C)O)(NC(=O)[C@]3(NC(=O)[C@@H](NC([C@@H](NC([C@H](CCCNC(=N)N)N)=O)CC(O)=O)=O)CSSC[C@]4(C(=O)N[C@@H](CCCCN)C(=O)N5[C@](C(=O)N[C@@H](CCSC)C(=O)N[C@@H](CCCCN)C(=O)N[C@@](CSSC3)(C(=O)N[C@H](C(N[C@H](C(N)=O)C)=O)CSSC[C@](NC(=O)[C@H](CCCCN)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@]6(N1C[C@H](O)C6)[H])(C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(O)=O)C(=O)N[C@@H](CCCNC(=N)N)C(=O)N[C@@H](CCCNC(=N)N)C(=O)N4)[H])[H])(C[C@@H](O)C5)[H])[H])[H])[H])C[C@H](O)C2)[H]]

[1]orres NS. Activation of reverse Na+-Ca2+ exchanger by skeletal Na+ channel isoform increases excitation-contraction coupling efficiency in rabbit cardiomyocytes. Am J Physiol Heart Circ Physiol. 2021 Feb 1;320(2):H593-H603.|[2]Garcia N, et al. Involvement of the Voltage-Gated Calcium Channels L- P/Q- and N-Types in Synapse Elimination During Neuromuscular Junction Development. Mol Neurobiol. 2022 Jul;59(7):4044-4064.|[3]Hill JM, et al. Three-dimensional solution structure of mu-conotoxin GIIIB, a specific blocker of skeletal muscle sodium channels. Biochemistry. 1996 Jul 9;35(27):8824-35.