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Entry version 129 (25 May 2022)
Sequence version 1 (21 Jul 1986)
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Protein

Alpha-cobratoxin

Gene
N/A
Organism
Naja kaouthia (Monocled cobra) (Naja siamensis)
Status
Reviewed-Annotation score:

Annotation score:5 out of 5

<p>The annotation score provides a heuristic measure of the annotation content of a UniProtKB entry or proteome. This score <strong>cannot</strong> be used as a measure of the accuracy of the annotation as we cannot define the 'correct annotation' for any given protein.<p><a href='/help/annotation_score' target='_top'>More...</a></p>
-Experimental evidence at protein leveli <p>This indicates the type of evidence that supports the existence of the protein. Note that the 'protein existence' evidence does not give information on the accuracy or correctness of the sequence(s) displayed.<p><a href='/help/protein_existence' target='_top'>More...</a></p>

<p>This section provides any useful information about the protein, mostly biological knowledge.<p><a href='/help/function_section' target='_top'>More...</a></p>Functioni

Monomer: binds with high affinity to muscular (alpha-1-beta-1-gamma-delta/CHRNA1-CHRNB1-CHRNG-CHRND) nAChR (tested on Torpedo californica, Kd=0.2-4.5 nM) and neuronal alpha-7/CHRNA7 nicotinic acetylcholine receptors (Kd=13-105 nM) (PubMed:18381281, PubMed:9305882, PubMed:22223648).

Also inhibits GABA(A) channels (PubMed:26221036).

Heteropentamer targets studied are composed of alpha-1-beta-3-gamma-2 (GABRA1-GABRB3-GABRG2) subunits (IC50=236 nM), alpha-1-beta-2-gamma-2 (GABRA1-GABRB2-GABRG2) subunits (IC50=469 nM), alpha-2-beta-2-gamma-2 (GABRA2-GABRB2-GABRG2) subunits (IC50=485 nM), alpha-5-beta-3-gamma-2 (GABRA5-GABRB3-GABRG2) subunits (IC50=635 nM), and alpha-2-beta-3-gamma-2 (GABRA2-GABRB3-GABRG2) subunits (IC50=1099 nM) (activated by 10 µM GABA) (PubMed:26221036).

4 Publications

Homodimer: binds with high affinity (but lower than the monomeric form) to muscular (IC50=9.7 nM) and with low affinity to neuronal alpha-7/CHRNA7 nAChRs (IC50=1370 nM) (PubMed:22223648).

However, it acquires (compared to the monomeric form) the capacity to block alpha-3/beta-2 (CHRNA3/CHRNB2) nAChRs (PubMed:18381281).

2 Publications

Heterodimer with cytotoxin 3 (AC P01446): is slightly more active than the homodimer in inhibiting alpha-7/CHRNA7 nAChR and is considerably more active in blocking the alpha-3-beta-2/CHRNA3-CHRNB2 nAChR.

1 Publication

Miscellaneous

The monomeric form has no effect on alpha-3/beta-2 (CHRNA3/CHRNB2) nAChR (PubMed:18381281). It does not show any blockade of the nicotine-evoked release of dopamine (PubMed:9840221) and does not affect ACh release.2 Publications
Exists in two forms, due to cis-trans isomerization at 6-Thr-Pro-7 (Probable). In the dimeric form, the Pro-7 is extended away from the toxin core whereas in the monomeric form, Pro-7 makes a turn (PubMed:22223648).Curated1 Publication

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
<p>This subsection describes interesting single amino acid sites on the sequence that are not defined in any other subsection. This subsection can be displayed in different sections ('Function', 'PTM / Processing', 'Pathology and Biotech') according to its content.<p><a href='/help/site' target='_top'>More...</a></p>Sitei23Binds to Torpedo AChR1 Publication1
Sitei25Binds to both neuronal alpha-7/CHRNA7 and Torpedo AChRs2 Publications1
Sitei27Binds to both neuronal alpha-7/CHRNA7 and Torpedo AChRs2 Publications1
Sitei28Binds to alpha-7/CHRNA7 AChR1 Publication1
Sitei29Binds to both neuronal alpha-7/CHRNA7 and Torpedo AChRs2 Publications1
Sitei33Binds to both neuronal alpha-7/CHRNA7 and Torpedo AChRs2 Publications1
Sitei35Binds to alpha-7/CHRNA7 AChR1 Publication1
Sitei36Binds to both neuronal alpha-7/CHRNA7 and Torpedo AChRs, may be important for inhibition of GABA(A) receptors1 Publication2 Publications1
Sitei49Binds to Torpedo AChR1 Publication1
Sitei65Binds to both neuronal alpha-7/CHRNA7 and Torpedo AChRs2 Publications1

<p>The <a href="http://www.geneontology.org/">Gene Ontology (GO)</a> project provides a set of hierarchical controlled vocabulary split into 3 categories:<p><a href='/help/gene_ontology' target='_top'>More...</a></p>GO - Molecular functioni

<p>UniProtKB Keywords constitute a <a href="http://www.uniprot.org/keywords">controlled vocabulary</a> with a hierarchical structure. Keywords summarise the content of a UniProtKB entry and facilitate the search for proteins of interest.<p><a href='/help/keywords' target='_top'>More...</a></p>Keywordsi

Molecular functionAcetylcholine receptor inhibiting toxin, Ion channel impairing toxin, Neurotoxin, Postsynaptic neurotoxin, Toxin

<p>This section provides information about the protein and gene name(s) and synonym(s) and about the organism that is the source of the protein sequence.<p><a href='/help/names_and_taxonomy_section' target='_top'>More...</a></p>Names & Taxonomyi

<p>This subsection of the <a href="http://www.uniprot.org/help/names%5Fand%5Ftaxonomy%5Fsection">Names and taxonomy</a> section provides an exhaustive list of all names of the protein, from commonly used to obsolete, to allow unambiguous identification of a protein.<p><a href='/help/protein_names' target='_top'>More...</a></p>Protein namesi
Recommended name:
Alpha-cobratoxin7 Publications
Short name:
Alpha-CT2 Publications
Short name:
Alpha-CbT1 Publication
Short name:
Alpha-Cbtx6 Publications
Short name:
Alpha-CtxCurated
Alternative name(s):
Alpha-elapitoxin-Nk2aCurated
Short name:
Alpha-EPTX-Nk2aCurated
Long neurotoxin 1
Siamensis 31 Publication
<p>This subsection of the <a href="http://www.uniprot.org/help/names%5Fand%5Ftaxonomy%5Fsection">Names and taxonomy</a> section provides information on the name(s) of the organism that is the source of the protein sequence.<p><a href='/help/organism-name' target='_top'>More...</a></p>OrganismiNaja kaouthia (Monocled cobra) (Naja siamensis)
<p>This subsection of the <a href="http://www.uniprot.org/help/names%5Fand%5Ftaxonomy%5Fsection">Names and taxonomy</a> section shows the unique identifier assigned by the NCBI to the source organism of the protein. This is known as the 'taxonomic identifier' or 'taxid'.<p><a href='/help/taxonomic_identifier' target='_top'>More...</a></p>Taxonomic identifieri8649 [NCBI]
<p>This subsection of the <a href="http://www.uniprot.org/help/names%5Fand%5Ftaxonomy%5Fsection">Names and taxonomy</a> section contains the taxonomic hierarchical classification lineage of the source organism. It lists the nodes as they appear top-down in the taxonomic tree, with the more general grouping listed first.<p><a href='/help/taxonomic_lineage' target='_top'>More...</a></p>Taxonomic lineageiEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiLepidosauriaSquamataBifurcataUnidentataEpisquamataToxicoferaSerpentesColubroideaElapidaeElapinaeNaja

<p>This section provides information on the location and the topology of the mature protein in the cell.<p><a href='/help/subcellular_location_section' target='_top'>More...</a></p>Subcellular locationi

Keywords - Cellular componenti

Secreted

<p>This section provides information on the disease(s) and phenotype(s) associated with a protein.<p><a href='/help/pathology_and_biotech_section' target='_top'>More...</a></p>Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
<p>This subsection of the <a href="http://www.uniprot.org/manual/pathology%5Fand%5Fbiotech%5Fsection">'Pathology and Biotech'</a> section describes the effect of the experimental mutation of one or more amino acid(s) on the biological properties of the protein.<p><a href='/help/mutagen' target='_top'>More...</a></p>Mutagenesisi23K → E: 2-fold and 28-fold decrease in affinity for Torpedo AChRs. 1 Publication1
Mutagenesisi25W → A: 11-fold decrease in affinity for Torpedo AChRs and 6-fold decrease in affinity for neuronal alpha-7/CHRNA7 AChR. 2 Publications1
Mutagenesisi27D → R: 31-fold decrease in affinity for Torpedo AChRs and 50-fold decrease in affinity for neuronal alpha-7/CHRNA7 AChR. 2 Publications1
Mutagenesisi28A → G: 5-fold decrease in affinity for neuronal alpha-7/CHRNA7 AChR. 1 Publication1
Mutagenesisi29F → A: 12-fold decrease in affinity for Torpedo AChRs and 74-fold decrease in affinity for neuronal alpha-7/CHRNA7 AChR. 2 Publications1
Mutagenesisi33R → E: 767-fold decrease in affinity for Torpedo AChRs and 339-fold decrease in affinity for neuronal alpha-7/CHRNA7 AChR. 2 Publications1
Mutagenesisi35K → A: 11-fold decrease in affinity for neuronal alpha-7/CHRNA7 AChR. 1 Publication1
Mutagenesisi36R → A: 16-fold decrease in affinity for Torpedo AChRs. 2 Publications1
Mutagenesisi49K → E: 3-fold and 53-fold decrease in affinity for Torpedo AChRs. 1 Publication1
Mutagenesisi65F → A: 7-fold decrease in affinity for Torpedo AChRs and 15-fold decrease in affinity for neuronal alpha-7/CHRNA7 AChR. 2 Publications1

<p>This section describes post-translational modifications (PTMs) and/or processing events.<p><a href='/help/ptm_processing_section' target='_top'>More...</a></p>PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
<p>This subsection of the 'PTM / Processing' section describes the extent of a polypeptide chain in the mature protein following processing or proteolytic cleavage.<p><a href='/help/chain' target='_top'>More...</a></p>ChainiPRO_00000935541 – 71Alpha-cobratoxin1 PublicationAdd BLAST71

Amino acid modifications

Feature keyPosition(s)DescriptionActionsGraphical viewLength
<p>This subsection of the PTM / Processing":/help/ptm_processing_section section describes the positions of cysteine residues participating in disulfide bonds.<p><a href='/help/disulfid' target='_top'>More...</a></p>Disulfide bondi3 ↔ 20In monomer, partialCombined sources6 Publications
Disulfide bondi3Interchain (with C-20); in homodimer; partialCombined sources1 Publication
Disulfide bondi14 ↔ 41Combined sources7 Publications
Disulfide bondi20Interchain (with C-3); in homodimer; partialCombined sources1 Publication
Disulfide bondi26 ↔ 30Combined sources7 Publications
Disulfide bondi45 ↔ 56Combined sources7 Publications
Disulfide bondi57 ↔ 62Combined sources7 Publications

<p>This subsection of the <a href="http://www.uniprot.org/help/ptm%5Fprocessing%5Fsection">PTM/processing</a> section describes post-translational modifications (PTMs). This subsection <strong>complements</strong> the information provided at the sequence level or describes modifications for which <strong>position-specific data is not yet available</strong>.<p><a href='/help/post-translational_modification' target='_top'>More...</a></p>Post-translational modificationi

In homodimer alpha-cobratoxin, selective reduction of Cys(26)-Cys(30) in one subunit does not affect the activity against the alpha-7/CHRNA7 nAChR, whereas its reduction in both subunits almost prevents alpha-7/CHRNA7 nAChR recognition. On the contrary, reduction of one or both Cys(26)-Cys(30) disulfide bonds in the homodimer considerably potentiates inhibition of the alpha-3-beta-2/CHRNA3-CHRNB2 nAChR by the toxin.1 Publication

Keywords - PTMi

Disulfide bond

<p>This section provides information on the expression of a gene at the mRNA or protein level in cells or in tissues of multicellular organisms.<p><a href='/help/expression_section' target='_top'>More...</a></p>Expressioni

<p>This subsection of the 'Expression' section provides information on the expression of a gene at the mRNA or protein level in cells or in tissues of multicellular organisms. By default, the information is derived from experiments at the mRNA level, unless specified 'at protein level'.<br></br>Examples: <a href="http://www.uniprot.org/uniprot/P92958#expression">P92958</a>, <a href="http://www.uniprot.org/uniprot/Q8TDN4#expression">Q8TDN4</a>, <a href="http://www.uniprot.org/uniprot/O14734#expression">O14734</a><p><a href='/help/tissue_specificity' target='_top'>More...</a></p>Tissue specificityi

Expressed by the venom gland.Curated

<p>This section provides information on the quaternary structure of a protein and on interaction(s) with other proteins or protein complexes.<p><a href='/help/interaction_section' target='_top'>More...</a></p>Interactioni

<p>This subsection of the <a href="http://www.uniprot.org/help/interaction%5Fsection">'Interaction'</a> section provides information about the protein quaternary structure and interaction(s) with other proteins or protein complexes (with the exception of physiological receptor-ligand interactions which are annotated in the <a href="http://www.uniprot.org/help/function%5Fsection">'Function'</a> section).<p><a href='/help/subunit_structure' target='_top'>More...</a></p>Subunit structurei

Monomer, homo- or heterodimer with cytotoxins 1 (P60305), 2 (AC P01445), and 3 (AC P01446); disulfide-linked.

8 Publications

<p>This section provides information on the tertiary and secondary structure of a protein.<p><a href='/help/structure_section' target='_top'>More...</a></p>Structurei

Secondary structure

171
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details

3D structure databases

AlphaFold Protein Structure Database

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AlphaFoldDBi
P01391

SWISS-MODEL Repository - a database of annotated 3D protein structure models

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SMRi
P01391

Database of comparative protein structure models

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ModBasei
Search...

Protein Data Bank in Europe - Knowledge Base

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PDBe-KBi
Search...

Miscellaneous databases

Relative evolutionary importance of amino acids within a protein sequence

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EvolutionaryTracei
P01391

<p>This section provides information on sequence similarities with other proteins and the domain(s) present in a protein.<p><a href='/help/family_and_domains_section' target='_top'>More...</a></p>Family & Domainsi

<p>This subsection of the 'Family and domains' section provides information about the sequence similarity with other proteins.<p><a href='/help/sequence_similarities' target='_top'>More...</a></p>Sequence similaritiesi

Family and domain databases

Conserved Domains Database

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CDDi
cd00206, snake_toxin, 1 hit

Gene3D Structural and Functional Annotation of Protein Families

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Gene3Di
2.10.60.10, 1 hit

Integrated resource of protein families, domains and functional sites

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InterProi
View protein in InterPro
IPR003571, Snake_3FTx
IPR045860, Snake_toxin-like_sf
IPR018354, Snake_toxin_con_site

Superfamily database of structural and functional annotation

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SUPFAMi
SSF57302, SSF57302, 1 hit

PROSITE; a protein domain and family database

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PROSITEi
View protein in PROSITE
PS00272, SNAKE_TOXIN, 1 hit

<p>This section displays by default the canonical protein sequence and upon request all isoforms described in the entry. It also includes information pertinent to the sequence(s), including <a href="http://www.uniprot.org/help/sequence%5Flength">length</a> and <a href="http://www.uniprot.org/help/sequences">molecular weight</a>. The information is filed in different subsections. The current subsections and their content are listed below:<p><a href='/help/sequences_section' target='_top'>More...</a></p>Sequencei

<p>This subsection of the <a href="http://www.uniprot.org/help/sequences%5Fsection">Sequence</a> section indicates if the <a href="http://www.uniprot.org/help/canonical%5Fand%5Fisoforms">canonical sequence</a> displayed by default in the entry is complete or not.<p><a href='/help/sequence_status' target='_top'>More...</a></p>Sequence statusi: Complete.

P01391-1 [UniParc]FASTAAdd to basket
« Hide
        10         20         30         40         50
IRCFITPDIT SKDCPNGHVC YTKTWCDAFC SIRGKRVDLG CAATCPTVKT
60 70
GVDIQCCSTD NCNPFPTRKR P
Length:71
Mass (Da):7,831
Last modified:July 21, 1986 - v1
<p>The checksum is a form of redundancy check that is calculated from the sequence. It is useful for tracking sequence updates.</p> <p>It should be noted that while, in theory, two different sequences could have the same checksum value, the likelihood that this would happen is extremely low.</p> <p>However UniProtKB may contain entries with identical sequences in case of multiple genes (paralogs).</p> <p>The checksum is computed as the sequence 64-bit Cyclic Redundancy Check value (CRC64) using the generator polynomial: x<sup>64</sup> + x<sup>4</sup> + x<sup>3</sup> + x + 1. The algorithm is described in the ISO 3309 standard. </p> <p class="publication">Press W.H., Flannery B.P., Teukolsky S.A. and Vetterling W.T.<br /> <strong>Cyclic redundancy and other checksums</strong><br /> <a href="http://www.nrbook.com/b/bookcpdf.php">Numerical recipes in C 2nd ed., pp896-902, Cambridge University Press (1993)</a>)</p> Checksum:i6F07ADD885E9AC33
GO

Sequence databases

Protein sequence database of the Protein Information Resource

More...
PIRi
A01662, N2NJ1S

<p>This section provides links to proteins that are similar to the protein sequence(s) described in this entry at different levels of sequence identity thresholds (100%, 90% and 50%) based on their membership in UniProt Reference Clusters (<a href="http://www.uniprot.org/help/uniref">UniRef</a>).<p><a href='/help/similar_proteins_section' target='_top'>More...</a></p>Similar proteinsi

<p>This section is used to point to information related to entries and found in data collections other than UniProtKB.<p><a href='/help/cross_references_section' target='_top'>More...</a></p>Cross-referencesi

Sequence databases

PIRiA01662, N2NJ1S

3D structure databases

Select the link destinations:

Protein Data Bank Europe

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PDBei

Protein Data Bank RCSB

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RCSB PDBi

Protein Data Bank Japan

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PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1CTXX-ray2.80A1-71[»]
1LXGNMR-A1-71[»]
1LXHNMR-A1-71[»]
1YI5X-ray4.20F/G/H/I/J1-71[»]
4AEAX-ray1.94A/B1-71[»]
6ZFMX-ray1.90A/B/D/E1-71[»]
AlphaFoldDBiP01391
SMRiP01391
ModBaseiSearch...
PDBe-KBiSearch...

Miscellaneous databases

EvolutionaryTraceiP01391

Family and domain databases

CDDicd00206, snake_toxin, 1 hit
Gene3Di2.10.60.10, 1 hit
InterProiView protein in InterPro
IPR003571, Snake_3FTx
IPR045860, Snake_toxin-like_sf
IPR018354, Snake_toxin_con_site
SUPFAMiSSF57302, SSF57302, 1 hit
PROSITEiView protein in PROSITE
PS00272, SNAKE_TOXIN, 1 hit

MobiDB: a database of protein disorder and mobility annotations

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MobiDBi
Search...

<p>This section provides general information on the entry.<p><a href='/help/entry_information_section' target='_top'>More...</a></p>Entry informationi

<p>This subsection of the 'Entry information' section provides a mnemonic identifier for a UniProtKB entry, but it is not a stable identifier. Each reviewed entry is assigned a unique entry name upon integration into UniProtKB/Swiss-Prot.<p><a href='/help/entry_name' target='_top'>More...</a></p>Entry namei3L21_NAJKA
<p>This subsection of the 'Entry information' section provides one or more accession number(s). These are stable identifiers and should be used to cite UniProtKB entries. Upon integration into UniProtKB, each entry is assigned a unique accession number, which is called 'Primary (citable) accession number'.<p><a href='/help/accession_numbers' target='_top'>More...</a></p>AccessioniPrimary (citable) accession number: P01391
<p>This subsection of the 'Entry information' section shows the date of integration of the entry into UniProtKB, the date of the last sequence update and the date of the last annotation modification ('Last modified'). The version number for both the entry and the <a href="http://www.uniprot.org/help/canonical%5Fand%5Fisoforms">canonical sequence</a> are also displayed.<p><a href='/help/entry_history' target='_top'>More...</a></p>Entry historyiIntegrated into UniProtKB/Swiss-Prot: July 21, 1986
Last sequence update: July 21, 1986
Last modified: May 25, 2022
This is version 129 of the entry and version 1 of the sequence. See complete history.
<p>This subsection of the 'Entry information' section indicates whether the entry has been manually annotated and reviewed by UniProtKB curators or not, in other words, if the entry belongs to the Swiss-Prot section of UniProtKB (<strong>reviewed</strong>) or to the computer-annotated TrEMBL section (<strong>unreviewed</strong>).<p><a href='/help/entry_status' target='_top'>More...</a></p>Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programAnimal Toxin Annotation Program
Annotation programChordata Protein Annotation Program

<p>This section contains any relevant information that doesn't fit in any other defined sections<p><a href='/help/miscellaneous_section' target='_top'>More...</a></p>Miscellaneousi

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
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