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P50983 (CA1_CONIM) Reviewed, UniProtKB/Swiss-Prot

Last modified July 24, 2013. Version 83. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (2) | Third-party data text xml rdf/xml gff fasta
to top of pageNames·Attributes·General annotation·Ontologies·Sequence annotation·Sequences·References·Cross-refs·Entry info·DocumentsCustomize order

Names and origin

Protein namesRecommended name:
Alpha-conotoxin ImI

Short name=Alpha-CTx ImI
OrganismConus imperialis (Imperial cone)
Taxonomic identifier35631 [NCBI]
Taxonomic lineageEukaryotaMetazoaLophotrochozoaMolluscaGastropodaCaenogastropodaHypsogastropodaNeogastropodaConoideaConidaeConus

Protein attributes

Sequence length17 AA.
Sequence statusFragment.
Sequence processingThe displayed sequence is further processed into a mature form.
Protein existenceEvidence at protein level

General annotation (Comments)

Function

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). 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. Acts voltage-independently. Is highly active against the neuromuscular receptor in frog. Ref.2

Subcellular location

Secreted.

Tissue specificity

Expressed by the venom duct.

Domain

The cysteine framework is I (CC-C-C).

Post-translational modification

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

Sequence similarities

Belongs to the conotoxin A superfamily.

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Propeptide‹1 – 4›4
PRO_0000273426
Peptide5 – 1612Alpha-conotoxin ImI Ref.2
PRO_0000034877

Amino acid modifications

Modified residue161Cysteine amide
Disulfide bond6 ↔ 12 Ref.2 Ref.5 Ref.6 Ref.7 Ref.8 Ref.9 Ref.10
Disulfide bond7 ↔ 16 Ref.2 Ref.5 Ref.6 Ref.7 Ref.8 Ref.9 Ref.10

Experimental info

Mutagenesis91D → L: Reduction of toxicity. Ref.10
Mutagenesis111R → L: Reduction of toxicity. Ref.10
Mutagenesis151R → E: No loss of activity. Ref.10
Non-terminal residue11

Secondary structure

...... 17
Helix Strand Turn

Details...

Sequences

Sequence LengthMass (Da)Tools
P50983 [UniParc].

Last modified January 16, 2004. Version 2.
Checksum: 9590D9CEA50279CF

FASTA171,938
        10 
IVRRGCCSDP RCAWRCG 

« Hide

References

[1]"Alpha-conotoxins ImI and ImII: similar alpha 7 nicotinic receptor antagonists act at different sites."
Ellison M.A., McIntosh J.M., Olivera B.M.
J. Biol. Chem. 278:757-764(2003) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], SYNTHESIS OF 5-16.
Tissue: Venom duct.
[2]"A nicotinic acetylcholine receptor ligand of unique specificity, alpha-conotoxin ImI."
McIntosh J.M., Yoshikami D., Mahe E., Nielsen D.B., Rivier J.E., Gray W.R., Olivera B.M.
J. Biol. Chem. 269:16733-16739(1994) [PubMed] [Europe PMC] [Abstract]
Cited for: PROTEIN SEQUENCE OF 5-16, FUNCTION, SYNTHESIS OF 5-16, DISULFIDE BONDS.
Tissue: Venom.
[3]"Alpha-conotoxin ImI exhibits subtype-specific nicotinic acetylcholine receptor blockade: preferential inhibition of homomeric alpha 7 and alpha 9 receptors."
Johnson D.S., Martinez J., Elgoyhen A.B., Heinemann S.F., McIntosh J.M.
Mol. Pharmacol. 48:194-199(1995) [PubMed] [Europe PMC] [Abstract]
Cited for: CHARACTERIZATION.
[4]"Role of hydroxyprolines in the in vitro oxidative folding and biological activity of conotoxins."
Lopez-Vera E., Walewska A., Skalicky J.J., Olivera B.M., Bulaj G.
Biochemistry 47:1741-1751(2008) [PubMed] [Europe PMC] [Abstract]
Cited for: SYNTHESIS OF 5-16, ROLE OF HYDROXYLATION.
[5]"NMR solution structure of alpha-conotoxin ImI and comparison to other conotoxins specific for neuronal nicotinic acetylcholine receptors."
Rogers J.P., Luginbuehl P., Shen G.S., McCabe R.T., Stevens R.C., Wemmer D.E.
Biochemistry 38:3874-3882(1999) [PubMed] [Europe PMC] [Abstract]
Cited for: STRUCTURE BY NMR OF 5-16, DISULFIDE BONDS.
[6]"Solution structure of alpha-conotoxin ImI determined by two-dimensional NMR spectroscopy."
Gouda H., Hirono S.
Biochim. Biophys. Acta 1431:384-394(1999) [PubMed] [Europe PMC] [Abstract]
Cited for: STRUCTURE BY NMR OF 5-16, DISULFIDE BONDS.
[7]"NMR spatial structure of alpha-conotoxin ImI reveals a common scaffold in snail and snake toxins recognizing neuronal nicotinic acetylcholine receptors."
Maslennikov I.V., Shenkarev Z.O., Zhmak M.N., Ivanov V.T., Methfessel C., Tsetlin V.I., Arseniev A.S.
FEBS Lett. 444:275-280(1999) [PubMed] [Europe PMC] [Abstract]
Cited for: STRUCTURE BY NMR OF 5-16, DISULFIDE BONDS.
[8]"Minimal conformation of the alpha-conotoxin ImI for the alpha7 neuronal nicotinic acetylcholine receptor recognition: correlated CD, NMR and binding studies."
Lamthanh H., Jegou-Matheron C., Servent D., Menez A., Lancelin J.-M.
FEBS Lett. 454:293-298(1999) [PubMed] [Europe PMC] [Abstract]
Cited for: STRUCTURE BY NMR OF 5-16, DISULFIDE BONDS.
[9]"Solution structure of alpha-conotoxin ImI by 1H nuclear magnetic resonance."
Gehrmann J., Daly N.L., Alewood P.F., Craik D.J.
J. Med. Chem. 42:2364-2372(1999) [PubMed] [Europe PMC] [Abstract]
Cited for: STRUCTURE BY NMR OF 5-16, DISULFIDE BONDS.
[10]"Structure-activity relationships in a peptidic alpha7 nicotinic acetylcholine receptor antagonist."
Rogers J.P., Luginbuhl P., Pemberton K., Harty P., Wemmer D.E., Stevens R.C.
J. Mol. Biol. 304:911-926(2000) [PubMed] [Europe PMC] [Abstract]
Cited for: MUTAGENESIS OF ASP-9; ARG-11 AND ARG-15, STRUCTURE BY NMR OF 5-16 OF THESE THREE MUTANTS, DISULFIDE BONDS.
+Additional computationally mapped references.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ
AY159318 Genomic DNA. Translation: AAN78128.1.
PIRA53709.

3D structure databases

PDBe
RCSB PDB
PDBj
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-A7-16[»]
2BC8NMR-A8-15[»]
2BYPX-ray2.07F/G/H/I/J5-16[»]
2C9TX-ray2.25K/M/O/P/Q/R/S/T5-16[»]
ModBaseSearch...
MobiDBSearch...

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Organism-specific databases

ConoServer93. ImI precursor.

Family and domain databases

InterProIPR018072. Conotoxin_a-typ_CS.
[Graphical view]
PROSITEPS60014. ALPHA_CONOTOXIN. 1 hit.
[Graphical view]
ProtoNetSearch...

Other

EvolutionaryTraceP50983.

Entry information

Entry nameCA1_CONIM
AccessionPrimary (citable) accession number: P50983
Secondary accession number(s): Q8I6R4
Entry history
Integrated into UniProtKB/Swiss-Prot: October 1, 1996
Last sequence update: January 16, 2004
Last modified: July 24, 2013
This is version 83 of the entry and version 2 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programAnimal Toxin Annotation Program

Relevant documents

SIMILARITY comments

Index of protein domains and families

PDB cross-references

Index of Protein Data Bank (PDB) cross-references