ID   ELBH_ECOLX              Reviewed;         124 AA.
AC   P0CK94; P13811;
DT   08-MAR-2011, integrated into UniProtKB/Swiss-Prot.
DT   08-MAR-2011, sequence version 1.
DT   25-MAY-2022, entry version 41.
DE   RecName: Full=Heat-labile enterotoxin B chain;
DE   AltName: Full=LT-B, human;
DE   AltName: Full=LTH-B;
DE   Flags: Precursor;
GN   Name=eltB; Synonyms=ltpB;
OS   Escherichia coli.
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Enterobacteriaceae; Escherichia.
OX   NCBI_TaxID=562;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=Isolate H74-114;
RX   PubMed=3884513; DOI=10.1128/iai.48.1.73-77.1985;
RA   Leong J., Vinal A.C., Dallas W.S.;
RT   "Nucleotide sequence comparison between heat-labile toxin B-subunit
RT   cistrons from Escherichia coli of human and porcine origin.";
RL   Infect. Immun. 48:73-77(1985).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=ETEC LT 87;
RA   Germani Y., Desperrier J.-M.;
RL   Submitted (OCT-1996) to the EMBL/GenBank/DDBJ databases.
RN   [3]
RP   PROTEIN SEQUENCE OF 22-124.
RC   STRAIN=Isolate 240-3;
RX   PubMed=3333803; DOI=10.1016/0882-4010(87)90079-9;
RA   Tsuji T., Iida T., Honda T., Miwatani T., Nagahama M., Sakurai J., Wada K.,
RA   Matsubara H.;
RT   "A unique amino acid sequence of the B subunit of a heat-labile enterotoxin
RT   isolated from a human enterotoxigenic Escherichia coli.";
RL   Microb. Pathog. 2:381-390(1987).
RN   [4]
RP   DISCUSSION OF SEQUENCE.
RX   PubMed=7623669; DOI=10.1111/j.1365-2958.1995.tb02289.x;
RA   Domenighini M., Pizza M., Jobling M.G., Holmes R.K., Rappuoli R.;
RT   "Identification of errors among database sequence entries and comparison of
RT   correct amino acid sequences for the heat-labile enterotoxins of
RT   Escherichia coli and Vibrio cholerae.";
RL   Mol. Microbiol. 15:1165-1167(1995).
RN   [5]
RP   X-RAY CRYSTALLOGRAPHY (3.04 ANGSTROMS).
RX   PubMed=10085117; DOI=10.1016/s0021-9258(19)87394-5;
RA   Matkovic-Calogovic D., Loregian A., D'Acunto M.R., Battistutta R.,
RA   Tossi A., Palu G., Zanotti G.;
RT   "Crystal structure of the B subunit of Escherichia coli heat-labile
RT   enterotoxin carrying peptides with anti-herpes simplex virus type 1
RT   activity.";
RL   J. Biol. Chem. 274:8764-8769(1999).
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.
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DR   EMBL; M17874; AAA98064.1; -; Genomic_DNA.
DR   EMBL; X83966; CAA58800.1; -; Genomic_DNA.
DR   PIR; A01820; QLECB.
DR   RefSeq; WP_024167713.1; NZ_NLYI01000164.1.
DR   PDB; 1B44; X-ray; 3.30 A; D/E/F/G/H=22-123.
DR   PDB; 1LTR; X-ray; 3.04 A; D/E/F/G/H=22-123.
DR   PDB; 2O2L; X-ray; 2.53 A; D/E/F/G/H/I/J/K/L/M=22-124.
DR   PDB; 3EFX; X-ray; 1.94 A; D/E/F/G/H/I/J/K/L/M=26-122.
DR   PDBsum; 1B44; -.
DR   PDBsum; 1LTR; -.
DR   PDBsum; 2O2L; -.
DR   PDBsum; 3EFX; -.
DR   AlphaFoldDB; P0CK94; -.
DR   SMR; P0CK94; -.
DR   UniLectin; P0CK94; -.
DR   EvolutionaryTrace; P0CK94; -.
DR   GO; GO:0005576; C:extracellular region; IEA:InterPro.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   InterPro; IPR008992; Enterotoxin.
DR   InterPro; IPR001835; Enterotoxin_B.
DR   Pfam; PF01376; Enterotoxin_b; 1.
DR   PRINTS; PR00772; ENTEROTOXINB.
DR   SUPFAM; SSF50203; SSF50203; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Direct protein sequencing; Disulfide bond; Enterotoxin;
KW   Signal; Toxin; Virulence.
FT   SIGNAL          1..21
FT                   /evidence="ECO:0000269|PubMed:3333803"
FT   CHAIN           22..124
FT                   /note="Heat-labile enterotoxin B chain"
FT                   /id="PRO_0000019356"
FT   DISULFID        30..107
FT   VARIANT         34
FT                   /note="H -> R (in strain: Isolate 240-3)"
FT   VARIANT         96
FT                   /note="T -> A (in strain: Isolate 240-3)"
FT   HELIX           28..31
FT                   /evidence="ECO:0007829|PDB:3EFX"
FT   STRAND          36..43
FT                   /evidence="ECO:0007829|PDB:3EFX"
FT   STRAND          46..51
FT                   /evidence="ECO:0007829|PDB:3EFX"
FT   STRAND          59..62
FT                   /evidence="ECO:0007829|PDB:2O2L"
FT   STRAND          68..71
FT                   /evidence="ECO:0007829|PDB:3EFX"
FT   HELIX           83..95
FT                   /evidence="ECO:0007829|PDB:3EFX"
FT   STRAND          102..109
FT                   /evidence="ECO:0007829|PDB:1LTR"
FT   STRAND          115..122
FT                   /evidence="ECO:0007829|PDB:3EFX"
SQ   SEQUENCE   124 AA;  14027 MW;  E9F7F7C7B9D3BC47 CRC64;
     MNKVKFYVLF TALLSSLCAH GAPQSITELC SEYHNTQIYT INDKILSYTE SMAGKREMVI
     ITFKSGATFQ VEVPGSQHID SQKKAIERMK DTLRITYLTE TKIDKLCVWN NKTPNSIAAI
     SMEN