ID   E2AA_ECOLX              Reviewed;         259 AA.
AC   P13810;
DT   01-JAN-1990, integrated into UniProtKB/Swiss-Prot.
DT   01-JAN-1990, sequence version 1.
DT   03-AUG-2022, entry version 67.
DE   RecName: Full=Heat-labile enterotoxin IIA, A chain;
DE            Short=LT-IIA;
DE   Flags: Precursor;
OS   Escherichia coli.
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Enterobacteriaceae; Escherichia.
OX   NCBI_TaxID=562;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=SA53;
RX   PubMed=2822667; DOI=10.1128/jb.169.11.5180-5187.1987;
RA   Pickett C.L., Weinstein D.L., Holmes R.K.;
RT   "Genetics of type IIa heat-labile enterotoxin of Escherichia coli: operon
RT   fusions, nucleotide sequence, and hybridization studies.";
RL   J. Bacteriol. 169:5180-5187(1987).
CC   -!- FUNCTION: The biological activity of the toxin is produced by the A
CC       chain, which activates intracellular adenyl cyclase.
CC   -!- SUBUNIT: Heterohexamer of one A chain and of five B chains.
CC   -!- SIMILARITY: Belongs to the enterotoxin A family. {ECO:0000305}.
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DR   EMBL; JQ031711; AAA24093.1; -; Genomic_DNA.
DR   PIR; A29831; A29831.
DR   AlphaFoldDB; P13810; -.
DR   SMR; P13810; -.
DR   GO; GO:0005615; C:extracellular space; IEA:InterPro.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   InterPro; IPR001144; Enterotoxin_A.
DR   Pfam; PF01375; Enterotoxin_a; 1.
DR   PRINTS; PR00771; ENTEROTOXINA.
PE   3: Inferred from homology;
KW   Disulfide bond; Enterotoxin; Signal; Toxin; Virulence.
FT   SIGNAL          1..18
FT   CHAIN           19..259
FT                   /note="Heat-labile enterotoxin IIA, A chain"
FT                   /id="PRO_0000019353"
FT   ACT_SITE        128
FT                   /evidence="ECO:0000250"
FT   BINDING         23..37
FT                   /ligand="NAD(+)"
FT                   /ligand_id="ChEBI:CHEBI:57540"
FT                   /evidence="ECO:0000250"
FT   DISULFID        203..215
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   259 AA;  29242 MW;  996F311A32CABEAA CRC64;
     MIKHVLLFFV FISFSVSAND FFRADSRTPD EIRRAGGLLP RGQQEAYERG TPININLYEH
     ARGTVTGNTR YNDGYVSTTV TLRQAHLIGQ NILGSYNEYY IYVVAPAPNL FDVNGVLGRY
     SPYPSENEFA ALGGIPLSQI IGWYRVSFGA IEGGMQRNRD YRGDLFRGLT VAPNEDGYQL
     AGFPSNFPAW REMPWSTFAP EQCVPNNKEF KGGVCISATN VLSKYDLMNF KKLLKRRLAL
     TFFMSEDDFI GVHGERDEL