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Entry version 142 (08 May 2019)
Sequence version 1 (23 Oct 1986)
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Protein

Cholera enterotoxin subunit A

Gene

ctxA

Organism
Vibrio cholerae serotype O1 (strain ATCC 39315 / El Tor Inaba N16961)
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

The A1 chain catalyzes the ADP-ribosylation of Gs alpha, a GTP-binding regulatory protein, to activate the adenylate cyclase. This leads to an overproduction of cAMP and eventually to a hypersecretion of chloride and bicarbonate followed by water, resulting in the characteristic cholera stool. The A2 chain tethers A1 to the pentameric ring.

Miscellaneous

After binding to gangliosides GM1 in lipid rafts, through the subunit B pentamer, the holotoxin and the gangliosides are internalized. The holotoxin remains bound to GM1 until arrival in the ER. The A subunit has previously been cleaved in the intestinal lumen but the A1 and A2 chains have remained associated. In the ER, the A subunit disulfide bridge is reduced, the A1 chain is unfolded by the PDI and disassembled from the rest of the toxin. Then, the membrane-associated ER oxidase ERO1 oxidizes PDI, which releases the unfolded A1 chain. The next step is the retrotranslocation of A1 into the cytosol. This might be mediated by the protein-conducting pore SEC61. Upon arrival in the cytosol, A1 refolds and avoids proteasome degradation. In one way or another, A1 finally reaches its target and induces toxicity.

Sites

Feature keyPosition(s)DescriptionActionsGraphical viewLength
<p>This subsection of the <a href="http://www.uniprot.org/help/function_section">Function</a> section is used for enzymes and indicates the residues directly involved in catalysis.<p><a href='/help/act_site' target='_top'>More...</a></p>Active sitei130By similarity1

Regions

Feature keyPosition(s)DescriptionActionsGraphical viewLength
<p>This subsection of the <a href="http://www.uniprot.org/help/function_section">Function</a> section describes a region in the protein which binds nucleotide phosphates. It always involves more than one amino acid and includes all residues involved in nucleotide-binding.<p><a href='/help/np_bind' target='_top'>More...</a></p>Nucleotide bindingi25 – 28NAD1 Publication4
Nucleotide bindingi41 – 43NAD1 Publication3

<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

GO - Biological processi

<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 functionEnterotoxin, Glycosyltransferase, Toxin, Transferase
LigandNAD

Enzyme and pathway databases

BioCyc Collection of Pathway/Genome Databases

More...
BioCyci
MetaCyc:VC1457-MONOMER
VCHO:VC1457-MONOMER

<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:
Cholera enterotoxin subunit A
Alternative name(s):
Cholera enterotoxin, A chain
Cleaved into the following 2 chains:
Cholera enterotoxin subunit A1 (EC:2.4.2.-)
Alternative name(s):
Cholera enterotoxin A1 chain
Cholera enterotoxin alpha chain
NAD(+)--diphthamide ADP-ribosyltransferase
Alternative name(s):
Cholera enterotoxin A2 chain
Cholera enterotoxin gamma chain
<p>This subsection of the <a href="http://www.uniprot.org/help/names_and_taxonomy_section">Names and taxonomy</a> section indicates the name(s) of the gene(s) that code for the protein sequence(s) described in the entry. Four distinct tokens exist: ‘Name’, ‘Synonyms’, ‘Ordered locus names’ and ‘ORF names’.<p><a href='/help/gene_name' target='_top'>More...</a></p>Gene namesi
Name:ctxA
Synonyms:toxA
Ordered Locus Names:VC_1457
<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>OrganismiVibrio cholerae serotype O1 (strain ATCC 39315 / El Tor Inaba N16961)
<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 identifieri243277 [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 lineageiBacteriaProteobacteriaGammaproteobacteriaVibrionalesVibrionaceaeVibrio
<p>This subsection of the <a href="http://www.uniprot.org/help/names_and_taxonomy_section">Names and taxonomy</a> section is present for entries that are part of a <a href="http://www.uniprot.org/proteomes">proteome</a>, i.e. of a set of proteins thought to be expressed by organisms whose genomes have been completely sequenced.<p><a href='/help/proteomes_manual' target='_top'>More...</a></p>Proteomesi
  • UP000000584 <p>A UniProt <a href="http://www.uniprot.org/manual/proteomes_manual">proteome</a> can consist of several components. <br></br>The component name refers to the genomic component encoding a set of proteins.<p><a href='/help/proteome_component' target='_top'>More...</a></p> Componenti: Chromosome 1

<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

GO - Cellular componenti

<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 – 182 PublicationsAdd BLAST18
<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_000001934219 – 212Cholera enterotoxin subunit A1Add BLAST194
ChainiPRO_0000019343213 – 258Cholera enterotoxin subunit A2Add BLAST46

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 bondi205 ↔ 217Interchain (between A1 and A2 chains)

Keywords - PTMi

Disulfide bond

<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_section">'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_section">'Function'</a> section).<p><a href='/help/subunit_structure' target='_top'>More...</a></p>Subunit structurei

The holotoxin (choleragen) consists of a pentameric ring of B subunits whose central pore is occupied by the A subunit. The A subunit contains two chains, A1 and A2, linked by a disulfide bridge. Interaction with the host protein ARF6 causes a conformation change so that the enterotoxin subunit A1 can bind NAD and catalyze the ADP-ribosylation of the host Gs alpha.2 Publications

<p>This subsection of the '<a href="http://www.uniprot.org/help/interaction_section%27">Interaction</a> section provides information about binary protein-protein interactions. The data presented in this section are a quality-filtered subset of binary interactions automatically derived from the <a href="http://www.ebi.ac.uk/intact/">IntAct database</a>. It is updated on a monthly basis. Each binary interaction is displayed on a separate line.<p><a href='/help/binary_interactions' target='_top'>More...</a></p>Binary interactionsi

WithEntry#Exp.IntActNotes
ctxBP015565EBI-1038392,EBI-1038383

Protein-protein interaction databases

Database of interacting proteins

More...
DIPi
DIP-6255N

The Eukaryotic Linear Motif resource for Functional Sites in Proteins

More...
ELMi
P01555

Protein interaction database and analysis system

More...
IntActi
P01555, 2 interactors

STRING: functional protein association networks

More...
STRINGi
243277.VC_1457

<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

1258
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details

3D structure databases

Database of protein disorder

More...
DisProti
DP00250

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

More...
SMRi
P01555

Database of comparative protein structure models

More...
ModBasei
Search...

MobiDB: a database of protein disorder and mobility annotations

More...
MobiDBi
Search...

Miscellaneous databases

Relative evolutionary importance of amino acids within a protein sequence

More...
EvolutionaryTracei
P01555

<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 four C-terminal residues of the A2 chain occupy the central pore of the holotoxin. Deletion of these residues weakens the interaction between the A subunit and the B pentamer without impairing the pentamer formation.

<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 enterotoxin A family.Curated

Keywords - Domaini

Signal

Phylogenomic databases

evolutionary genealogy of genes: Non-supervised Orthologous Groups

More...
eggNOGi
ENOG4107927 Bacteria
ENOG410Y5VZ LUCA

KEGG Orthology (KO)

More...
KOi
K10928

Identification of Orthologs from Complete Genome Data

More...
OMAi
PRGHNEY

Family and domain databases

Integrated resource of protein families, domains and functional sites

More...
InterProi
View protein in InterPro
IPR001144 Enterotoxin_A

Pfam protein domain database

More...
Pfami
View protein in Pfam
PF01375 Enterotoxin_a, 1 hit

Protein Motif fingerprint database; a protein domain database

More...
PRINTSi
PR00771 ENTEROTOXINA

<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>. 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_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.

P01555-1 [UniParc]FASTAAdd to basket
« Hide
        10         20         30         40         50
MVKIIFVFFI FLSSFSYAND DKLYRADSRP PDEIKQSGGL MPRGQSEYFD
60 70 80 90 100
RGTQMNINLY DHARGTQTGF VRHDDGYVST SISLRSAHLV GQTILSGHST
110 120 130 140 150
YYIYVIATAP NMFNVNDVLG AYSPHPDEQE VSALGGIPYS QIYGWYRVHF
160 170 180 190 200
GVLDEQLHRN RGYRDRYYSN LDIAPAADGY GLAGFPPEHR AWREEPWIHH
210 220 230 240 250
APPGCGNAPR SSMSNTCDEK TQSLGVKFLD EYQSKVKRQI FSGYQSDIDT

HNRIKDEL
Length:258
Mass (Da):29,336
Last modified:October 23, 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:i0F7EBAE62069A5D0
GO

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
<p>This subsection of the ‘Sequence’ section reports difference(s) between the canonical sequence (displayed by default in the entry) and the different sequence submissions merged in the entry. These various submissions may originate from different sequencing projects, different types of experiments, or different biological samples. Sequence conflicts are usually of unknown origin.<p><a href='/help/conflict' target='_top'>More...</a></p>Sequence conflicti20D → N AA sequence (PubMed:7238869).Curated1
Sequence conflicti37S → R AA sequence (PubMed:955672).Curated1
Sequence conflicti39G → L AA sequence (PubMed:437113).Curated1
Sequence conflicti45 – 46QS → SE AA sequence (PubMed:437113).Curated2
Sequence conflicti111N → L AA sequence (PubMed:437113).Curated1
Sequence conflicti132S → A AA sequence (PubMed:437113).Curated1
Sequence conflicti213M → I in CAA24995 (PubMed:6646234).Curated1
Sequence conflicti247 – 248DI → ID AA sequence (PubMed:7028752).Curated2
Sequence conflicti256D → N AA sequence (PubMed:7028752).Curated1

Sequence databases

Select the link destinations:

EMBL nucleotide sequence database

More...
EMBLi

GenBank nucleotide sequence database

More...
GenBanki

DNA Data Bank of Japan; a nucleotide sequence database

More...
DDBJi
Links Updated
X00171 Genomic DNA Translation: CAA24995.1
X58785 Genomic DNA Translation: CAA41590.1
D30053 Genomic DNA Translation: BAA06290.1
X58786 Genomic DNA Translation: CAA41592.1
K02679 Genomic DNA Translation: AAA27514.1
AF175708 Genomic DNA Translation: AAD51359.1
AE003852 Genomic DNA Translation: AAF94614.1
K01170 Genomic DNA Translation: AAA27572.1
D30052 Genomic DNA Translation: BAA06288.1

Protein sequence database of the Protein Information Resource

More...
PIRi
A05129 XVVCA

NCBI Reference Sequences

More...
RefSeqi
NP_231100.1, NC_002505.1
WP_001881225.1, NC_002505.1

Genome annotation databases

Ensembl bacterial and archaeal genome annotation project

More...
EnsemblBacteriai
AAF94614; AAF94614; VC_1457

Database of genes from NCBI RefSeq genomes

More...
GeneIDi
2613963

KEGG: Kyoto Encyclopedia of Genes and Genomes

More...
KEGGi
vch:VC1457

Pathosystems Resource Integration Center (PATRIC)

More...
PATRICi
fig|243277.26.peg.1387

<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
X00171 Genomic DNA Translation: CAA24995.1
X58785 Genomic DNA Translation: CAA41590.1
D30053 Genomic DNA Translation: BAA06290.1
X58786 Genomic DNA Translation: CAA41592.1
K02679 Genomic DNA Translation: AAA27514.1
AF175708 Genomic DNA Translation: AAD51359.1
AE003852 Genomic DNA Translation: AAF94614.1
K01170 Genomic DNA Translation: AAA27572.1
D30052 Genomic DNA Translation: BAA06288.1
PIRiA05129 XVVCA
RefSeqiNP_231100.1, NC_002505.1
WP_001881225.1, NC_002505.1

3D structure databases

Select the link destinations:

Protein Data Bank Europe

More...
PDBei

Protein Data Bank RCSB

More...
RCSB PDBi

Protein Data Bank Japan

More...
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1S5BX-ray2.13A19-258[»]
1S5CX-ray2.50A19-258[»]
1S5DX-ray1.75A19-258[»]
1S5EX-ray1.90A/B19-258[»]
1S5FX-ray2.60A19-258[»]
1XTCX-ray2.40A19-212[»]
C213-258[»]
2A5DX-ray1.80B19-210[»]
2A5FX-ray2.02B19-210[»]
2A5GX-ray2.66B19-210[»]
DisProtiDP00250
SMRiP01555
ModBaseiSearch...
MobiDBiSearch...

Protein-protein interaction databases

DIPiDIP-6255N
ELMiP01555
IntActiP01555, 2 interactors
STRINGi243277.VC_1457

Protocols and materials databases

The DNASU plasmid repository

More...
DNASUi
2613963
Structural Biology KnowledgebaseSearch...

Genome annotation databases

EnsemblBacteriaiAAF94614; AAF94614; VC_1457
GeneIDi2613963
KEGGivch:VC1457
PATRICifig|243277.26.peg.1387

Phylogenomic databases

eggNOGiENOG4107927 Bacteria
ENOG410Y5VZ LUCA
KOiK10928
OMAiPRGHNEY

Enzyme and pathway databases

BioCyciMetaCyc:VC1457-MONOMER
VCHO:VC1457-MONOMER

Miscellaneous databases

EvolutionaryTraceiP01555

Protein Ontology

More...
PROi
PR:P01555

Family and domain databases

InterProiView protein in InterPro
IPR001144 Enterotoxin_A
PfamiView protein in Pfam
PF01375 Enterotoxin_a, 1 hit
PRINTSiPR00771 ENTEROTOXINA

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 nameiCHTA_VIBCH
<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: P01555
Secondary accession number(s): Q56634, Q9JPV1
<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: July 21, 1986
Last sequence update: October 23, 1986
Last modified: May 8, 2019
This is version 142 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 programProkaryotic 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, Complete proteome, Direct protein sequencing, Reference proteome

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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