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Entry version 72 (22 Nov 2017)
Sequence version 1 (01 Jun 2003)
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Protein

Potassium channel toxin gamma-KTx 1.1

Gene
N/A
Organism
Centruroides noxius (Mexican scorpion)
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

Blocks human and rat Kv11.1/KCNH2/ERG1 and Kv11.3/KCNH7/ERG3, as well as rat (but not human) Kv11.2/KCNH6/ERG2 (PubMed:11755529, PubMed:11864985, PubMed:16497878, PubMed:17369411, PubMed:20600425) by binding to channel outer vestibule (S5P domain) with a 1:1 stoichiometry (PubMed:11755529, PubMed:11864985, PubMed:17369411, PubMed:20600425). Inhibition data are the following: hERG1 (reversible, IC50~7 nM) (PubMed:11755529, PubMed:11864985, PubMed:16497878, PubMed:17369411, PubMed:20600425), rERG1 (reversible, Kd=6.8 nM) (PubMed:16497878), rERG2 (irreversible, Kd=2.8 nM) (PubMed:16497878), hERG3 (irreversible, Kd=4.05 nM) (PubMed:16497878) and rERG3 (reversible, Kd=38.1 nM) (PubMed:16497878) potassium channels. The toxin potency is not affected by elevating potassium ion concentration from 2 to 98 mM (PubMed:11864985). This toxin only blocks channels in a closed state (PubMed:12860380). At high toxin concentrations, block of Kv11.1/KCNH2/ERG1 macroscopic current is incomplete (93.5%). This suggests a kinetic mechanism model with two different states of toxin-channel binding (T+C=TC*=TC; in the TC* state, the toxin binds the channel but does not occlude the pore, whereas in the TC state the toxin binds and occludes the pore). In this model, incomplete block is explained by the relatively fast dissociation rate from the blocked channel conformation (TC) relative to the rate of conversion of the toxin-channel encounter complex (TC*) to the blocked channel conformation (TC) (PubMed:17369411).7 Publications

Miscellaneous

The affinity of the toxin for the channel decreases as temperature increases (Kd=7.3 nM and Kd=64 nM at 22 and 37 degrees Celsius, respectively), likely due to changes in the structure of the channel binding site.1 Publication
Does not affect the function of either mouse EAG/KCNH1 or ELK1 channels at concentration of 200 nM (PubMed:11755529). Does not inhibit hKv1.4/KCNA4, hKv4.3/KCND3, hKv2.1/KCNB1 and rKv7.1/KCNQ1 potassium channels at concentration of 50 nM (PubMed:11864985). Does not inhibit human Kv11.2/KCNH6/ERG2 (PubMed:16497878).3 Publications

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>Sitei33May represent the binding site1 Publication1
Sitei55Key residue on the interacting surface with the channel1 Publication1

<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 functionIon channel impairing toxin, Neurotoxin, Potassium channel impairing toxin, Toxin, Voltage-gated potassium channel impairing 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_and_taxonomy_section">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:
Potassium channel toxin gamma-KTx 1.11 Publication
Alternative name(s):
Ergtoxin1 Publication
Short name:
CnErg11 Publication
Short name:
CnErgTx11 Publication
Short name:
ErgTx1 Publication
Short name:
ErgTx11 Publication
<p>This subsection of the <a href="http://www.uniprot.org/help/names_and_taxonomy_section">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>OrganismiCentruroides noxius (Mexican scorpion)
<p>This subsection of the <a href="http://www.uniprot.org/help/names_and_taxonomy_section">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 identifieri6878 [NCBI]
<p>This subsection of the <a href="http://www.uniprot.org/help/names_and_taxonomy_section">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 lineageiEukaryotaMetazoaEcdysozoaArthropodaChelicerataArachnidaScorpionesButhidaButhoideaButhidaeCentruroides

<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

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

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_and_biotech_section">'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>Mutagenesisi38Q → A: 6-fold reduction in affinity for Kv11.1/KCNH2/ERG1 potassium channel (Kd=72.9 nM). 1 Publication1
Mutagenesisi55M → A: 30-fold reduction in affinity for Kv11.1/KCNH2/ERG1 potassium channel (Kd=303.4 nM). 1 Publication1
Mutagenesisi62A → T: No change in affinity for Kv11.1/KCNH2/ERG1 potassium channel (Kd=14.2 nM). 1 Publication1

<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 denotes the presence of an N-terminal signal peptide.<p><a href='/help/signal' target='_top'>More...</a></p>Signal peptidei1 – 201 PublicationAdd BLAST20
<p>This subsection of the ‘PTM / Processing’ section describes the extent of a polypeptide chain in the mature protein following processing.<p><a href='/help/chain' target='_top'>More...</a></p>ChainiPRO_000003536221 – 62Potassium channel toxin gamma-KTx 1.1Add BLAST42

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 bondi25 ↔ 432 Publications
Disulfide bondi31 ↔ 542 Publications
Disulfide bondi40 ↔ 592 Publications
Disulfide bondi44 ↔ 612 Publications

<p>This subsection of the <a href="http://www.uniprot.org/help/ptm_processing_section">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

After protein storage at -20 Celsius degrees during a couple of months, the Met-55 of a small number of toxins is naturally oxidized. This oxidized form is about three orders of magnitude less efficient (IC50=15 µM) than non-oxidized form.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 tertiary and secondary structure of a protein.<p><a href='/help/structure_section' target='_top'>More...</a></p>Structurei

Secondary structure

162
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details

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
1NE5NMR-A21-62[»]
1PX9NMR-A21-62[»]

Protein Model Portal of the PSI-Nature Structural Biology Knowledgebase

More...
ProteinModelPortali
Q86QT3

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

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SMRi
Q86QT3

Database of comparative protein structure models

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ModBasei
Search...

MobiDB: a database of protein disorder and mobility annotations

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MobiDBi
Search...

Miscellaneous databases

Relative evolutionary importance of amino acids within a protein sequence

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EvolutionaryTracei
Q86QT3

<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 general information on the biological role of a domain. The term ‘domain’ is intended here in its wide acceptation, it may be a structural domain, a transmembrane region or a functional domain. Several domains are described in this subsection.<p><a href='/help/domain_cc' target='_top'>More...</a></p>Domaini

The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin.
Has the CSalpha/beta fold, which comprises one or two short alpha helices connected to anti-parallel beta-sheets stabilized by three or four disulfide bonds.2 Publications

<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

Belongs to the ergtoxin family. Gamma-KTx 1 subfamily.Curated

Keywords - Domaini

Knottin, Signal

Family and domain databases

Gene3D Structural and Functional Annotation of Protein Families

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Gene3Di
3.30.30.10, 1 hit

Integrated resource of protein families, domains and functional sites

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InterProi
View protein in InterPro
IPR012622 Ergtoxin
IPR036574 Scorpion_toxin-like_sf

Pfam protein domain database

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Pfami
View protein in Pfam
PF08086 Toxin_17, 1 hit

ProDom; a protein domain database

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ProDomi
View protein in ProDom or Entries sharing at least one domain
PD736966 Ergtoxin, 1 hit

Superfamily database of structural and functional annotation

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SUPFAMi
SSF57095 SSF57095, 1 hit

PROSITE; a protein domain and family database

More...
PROSITEi
View protein in PROSITE
PS60026 ERGTX, 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_length">length</a> and <a href="http://www.uniprot.org/help/sequences">molecular weight</a>.<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_section">Sequence</a> section indicates if the <a href="http://www.uniprot.org/help/canonical_and_isoforms">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.

<p>This subsection of the <a href="http://www.uniprot.org/help/sequences_section">Sequence</a> section indicates if the <a href="http://www.uniprot.org/help/canonical_and_isoforms">canonical sequence</a> displayed by default in the entry is in its mature form or if it represents the precursor.<p><a href='/help/sequence_processing' target='_top'>More...</a></p>Sequence processingi: The displayed sequence is further processed into a mature form.

Q86QT3-1 [UniParc]FASTAAdd to basket
« Hide
        10         20         30         40         50
MKVLILIMII ASLMIMGVEM DRDSCVDKSR CAKYGYYQEC QDCCKNAGHN
60
GGTCMFFKCK CA
Length:62
Mass (Da):6,970
Last modified:June 1, 2003 - 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:i53F88F4B9F187E37
GO

<p>This subsection of the ‘Sequence’ section reports information derived from mass spectrometry experiments done on the entire protein or on biologically active derived peptide(s).<p><a href='/help/mass_spectrometry' target='_top'>More...</a></p>Mass spectrometryi

Molecular mass is 4730.8±0.4 Da from positions 21 - 62. Determined by MALDI. 1 Publication

Sequence databases

Select the link destinations:

EMBL nucleotide sequence database

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EMBLi

GenBank nucleotide sequence database

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GenBanki

DNA Data Bank of Japan; a nucleotide sequence database

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DDBJi
Links Updated
AY164271 mRNA Translation: AAO22234.1
AF288205 mRNA Translation: AAG38523.1

<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

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AY164271 mRNA Translation: AAO22234.1
AF288205 mRNA Translation: AAG38523.1

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1NE5NMR-A21-62[»]
1PX9NMR-A21-62[»]
ProteinModelPortaliQ86QT3
SMRiQ86QT3
ModBaseiSearch...
MobiDBiSearch...

Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Miscellaneous databases

EvolutionaryTraceiQ86QT3

Family and domain databases

Gene3Di3.30.30.10, 1 hit
InterProiView protein in InterPro
IPR012622 Ergtoxin
IPR036574 Scorpion_toxin-like_sf
PfamiView protein in Pfam
PF08086 Toxin_17, 1 hit
ProDomiView protein in ProDom or Entries sharing at least one domain
PD736966 Ergtoxin, 1 hit
SUPFAMiSSF57095 SSF57095, 1 hit
PROSITEiView protein in PROSITE
PS60026 ERGTX, 1 hit

ProtoNet; Automatic hierarchical classification of proteins

More...
ProtoNeti
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 nameiKGX11_CENNO
<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: Q86QT3
Secondary accession number(s): Q9GQ92
<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_and_isoforms">canonical sequence</a> are also displayed.<p><a href='/help/entry_history' target='_top'>More...</a></p>Entry historyiIntegrated into UniProtKB/Swiss-Prot: October 31, 2003
Last sequence update: June 1, 2003
Last modified: November 22, 2017
This is version 72 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

<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. Scorpion potassium channel toxins
    Nomenclature of scorpion potassium channel toxins and list of entries
  2. SIMILARITY comments
    Index of protein domains and families
  3. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
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