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Mu-conotoxin SIIIB

Conus striatus (Striated cone)
Reviewed-Annotation score: -Experimental evidence at protein leveli


Mu-conotoxins block voltage-gated sodium channels (VGSC). Potently displaces (125)I-TIIIA from native rat brain Nav1.2/SCN2A (IC50 is 5 nM) and muscle Nav1.4/SCN4A (IC50 is 3 nM) VGSCs. Potently and irreversibly inhibits current through Xenopus oocyte-expressed Nav1.2/SCN2A and Nav1.4/SCN4A.1 Publication

GO - Molecular functioni


Molecular functionIon channel impairing toxin, Neurotoxin, Toxin, Voltage-gated sodium channel impairing toxin

Names & Taxonomyi

Protein namesi
Recommended name:
Mu-conotoxin SIIIB
OrganismiConus striatus (Striated cone)
Taxonomic identifieri6493 [NCBI]
Taxonomic lineageiEukaryotaMetazoaLophotrochozoaMolluscaGastropodaCaenogastropodaNeogastropodaConoideaConidaeConusPionoconus

Organism-specific databases

ConoServeri1615 SIIIB

Subcellular locationi

Extracellular region or secreted Cytosol Plasma membrane Cytoskeleton Lysosome Endosome Peroxisome ER Golgi apparatus Nucleus Mitochondrion Manual annotation Automatic computational assertionGraphics by Christian Stolte; Source: COMPARTMENTS

Keywords - Cellular componenti


Pathology & Biotechi


Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi1 – 2QN → E: Slight decrease in affinity to Nav1.2/SCN2A and decrease in affinity to Nav1.4/SCN4A ([N2E]SIIIB(2-20)). 1 Publication2
Mutagenesisi1Q → E: Decrease of affinity to Nav1.2/SCN2A and important decrease to Nav1.4/SCN4A with shift of selectivity in favor of Nav1.2/SCN2A. 2 Publications1
Mutagenesisi1Q → ER: Slight increase of selectivity to Nav1.2/SCN2A and slight decrease of affinity to Nav1.4/SCN4A. 2 Publications1
Mutagenesisi1Q → R: Slight increase of affinity to Nav1.2/SCN2A and slight decrease of affinity to Nav1.4/SCN4A. 2 Publications1
Mutagenesisi1Missing : Increase of affinity to both Nav1.2/SCN2A and Nav1.4/SCN4A. 2 Publications1

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
PeptideiPRO_00003927281 – 20Mu-conotoxin SIIIBAdd BLAST20

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Modified residuei1Pyrrolidone carboxylic acid1 Publication1
Disulfide bondi3 ↔ 13By similarity
Disulfide bondi4 ↔ 19By similarity
Disulfide bondi8 ↔ 20By similarity
Modified residuei20Cysteine amide1 Publication1

Keywords - PTMi

Amidation, Disulfide bond, Pyrrolidone carboxylic acid


Tissue specificityi

Expressed by the venom duct.

Family & Domainsi


The cysteine framework is III (CC-C-C-CC). Classified in the M-5 branch, since 5 residues stand between the fourth and the fifth cysteine residues.

Sequence similaritiesi

Belongs to the conotoxin M superfamily.Curated


Sequence statusi: Complete.

P0CE77-1 [UniParc]FASTAAdd to basket
« Hide
        10         20
Mass (Da):2,145
Last modified:March 23, 2010 - v1

Mass spectrometryi

Molecular mass is 2120.7 Da from positions 1 - 20. Determined by ESI. 1 Publication

Similar proteinsi


3D structure databases


Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Organism-specific databases

ConoServeri1615 SIIIB

Family and domain databases


Entry informationi

Entry nameiCM3B_CONST
AccessioniPrimary (citable) accession number: P0CE77
Entry historyiIntegrated into UniProtKB/Swiss-Prot: March 23, 2010
Last sequence update: March 23, 2010
Last modified: September 12, 2018
This is version 20 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programAnimal Toxin Annotation Program


Keywords - Technical termi

Direct protein sequencing


  1. SIMILARITY comments
    Index of protein domains and families
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Main funding by: National Institutes of Health

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