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Protein

Alpha-conotoxin ImI

Gene
N/A
Organism
Conus imperialis (Imperial cone)
Status
Reviewed-Annotation score: Annotation score: 4 out of 5-Experimental evidence at protein leveli

Functioni

Alpha-conotoxins act on postsynaptic membranes, they bind to the nicotinic acetylcholine receptors (nAChR) and thus inhibit them. This toxin blocks mammalian neuronal nAChRs (alpha-3/beta-2 > alpha-7 > alpha-3/beta-4). Acts voltage-independently. Is highly active against the neuromuscular receptor in frog.1 Publication

Keywords - Molecular functioni

Acetylcholine receptor inhibiting toxin, Ion channel impairing toxin, Neurotoxin, Postsynaptic neurotoxin, Toxin

Names & Taxonomyi

Protein namesi
Recommended name:
Alpha-conotoxin ImI
Short name:
Alpha-CTx ImI
OrganismiConus imperialis (Imperial cone)
Taxonomic identifieri35631 [NCBI]
Taxonomic lineageiEukaryotaMetazoaLophotrochozoaMolluscaGastropodaCaenogastropodaHypsogastropodaNeogastropodaConoideaConidaeConus

Organism-specific databases

ConoServeri93. ImI precursor.

Subcellular locationi

GO - Cellular componenti

Complete GO annotation...

Keywords - Cellular componenti

Secreted

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi9D → L: Reduction of toxicity. 1 Publication1
Mutagenesisi11R → L: Reduction of toxicity. 1 Publication1
Mutagenesisi15R → E: No loss of activity. 1 Publication1

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
PropeptideiPRO_0000273426‹1 – 41 Publication›4
PeptideiPRO_00000348775 – 16Alpha-conotoxin ImIAdd BLAST12

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Disulfide bondi6 ↔ 16In Imi-ribbon form; alternate1 Publication
Disulfide bondi6 ↔ 12In Imi-globular form; alternate6 Publications
Disulfide bondi7 ↔ 16In Imi-globular form; alternate6 Publications
Disulfide bondi7 ↔ 12In Imi-ribbon form; alternate1 Publication
Modified residuei16Cysteine amide1

Post-translational modificationi

Not hydroxylated; hydroxylation, on a synthetic hydroxylated ImI, improves its folding but impairs its activity against target receptors.

Keywords - PTMi

Amidation, Cleavage on pair of basic residues, Disulfide bond

Expressioni

Tissue specificityi

Expressed by the venom duct.Curated

Interactioni

Protein-protein interaction databases

DIPiDIP-61127N.

Structurei

Secondary structure

117
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Helixi6 – 8Combined sources3
Turni10 – 12Combined sources3
Helixi13 – 15Combined sources3

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1CNLNMR-A5-16[»]
1E74NMR-A5-14[»]
1E75NMR-A5-16[»]
1E76NMR-A5-16[»]
1G2GNMR-A5-16[»]
1IM1NMR-A5-16[»]
1IMINMR-A5-16[»]
2BC7NMR-A5-16[»]
2BC8NMR-A5-16[»]
2BYPX-ray2.07F/G/H/I/J5-16[»]
2C9TX-ray2.25K/M/O/P/Q/R/S/T5-16[»]
2IGUNMR-A5-16[»]
2MOANMR-A5-16[»]
SMRiP50983.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP50983.

Family & Domainsi

Domaini

The cysteine framework is I (CC-C-C). Alpha4/3 pattern.

Sequence similaritiesi

Belongs to the conotoxin A superfamily.Curated

Family and domain databases

InterProiIPR018072. Conotoxin_a-typ_CS.
[Graphical view]
PROSITEiPS60014. ALPHA_CONOTOXIN. 1 hit.
[Graphical view]

Sequencei

Sequence statusi: Fragment.

Sequence processingi: The displayed sequence is further processed into a mature form.

P50983-1 [UniParc]FASTAAdd to basket

« Hide

        10 
IVRRGCCSDP RCAWRCG
Length:17
Mass (Da):1,938
Last modified:January 16, 2004 - v2
Checksum:i9590D9CEA50279CF
GO

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Non-terminal residuei11

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AY159318 Genomic DNA. Translation: AAN78128.1.
PIRiA53709.

Cross-referencesi

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AY159318 Genomic DNA. Translation: AAN78128.1.
PIRiA53709.

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1CNLNMR-A5-16[»]
1E74NMR-A5-14[»]
1E75NMR-A5-16[»]
1E76NMR-A5-16[»]
1G2GNMR-A5-16[»]
1IM1NMR-A5-16[»]
1IMINMR-A5-16[»]
2BC7NMR-A5-16[»]
2BC8NMR-A5-16[»]
2BYPX-ray2.07F/G/H/I/J5-16[»]
2C9TX-ray2.25K/M/O/P/Q/R/S/T5-16[»]
2IGUNMR-A5-16[»]
2MOANMR-A5-16[»]
SMRiP50983.
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

DIPiDIP-61127N.

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Organism-specific databases

ConoServeri93. ImI precursor.

Miscellaneous databases

EvolutionaryTraceiP50983.

Family and domain databases

InterProiIPR018072. Conotoxin_a-typ_CS.
[Graphical view]
PROSITEiPS60014. ALPHA_CONOTOXIN. 1 hit.
[Graphical view]
ProtoNetiSearch...

Entry informationi

Entry nameiCA1_CONIM
AccessioniPrimary (citable) accession number: P50983
Secondary accession number(s): Q8I6R4
Entry historyi
Integrated into UniProtKB/Swiss-Prot: October 1, 1996
Last sequence update: January 16, 2004
Last modified: November 2, 2016
This is version 93 of the entry and version 2 of the sequence. [Complete history]
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programAnimal Toxin Annotation Program

Miscellaneousi

Miscellaneous

This toxin is a substrate for a multienzyme complex that regulates its folding and assembly. This complex is composed of protein-disulfide isomerase (PDI), peptidyl-prolyl cis-trans isomerase (PPI) and immunoglobulin-binding protein (BiP). PDI catalyzes the oxidation and reduction of disulfide bonds. Oxidative folding rates are further increased in the presence of PPI with the maximum effect observed in the presence of both enzymes. In contrast, BiP is only observed to assist folding in the presence of microsomes, suggesting that additional cofactors are involved. This toxin has been observed in the venom as globular (disulfide pattern C1-C3 and C2-C4) and ribbon form (C1-C4 and C2-C3).1 Publication
Has no effect on nAChRs composed of alpha-2/beta-2, alpha-3/beta-2, alpha-4/beta-2, alpha-2/beta-4, alpha-3/beta-4, or alpha-4/beta-4 subunits.

Keywords - Technical termi

3D-structure, Direct protein sequencing

Documents

  1. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  2. SIMILARITY comments
    Index of protein domains and families

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.