ID   STXA_BPH19              Reviewed;         315 AA.
AC   P08026;
DT   01-AUG-1988, integrated into UniProtKB/Swiss-Prot.
DT   01-AUG-1988, sequence version 1.
DT   29-SEP-2021, entry version 97.
DE   RecName: Full=Shiga-like toxin 1 subunit A;
DE            Short=SLT-1 A subunit;
DE            Short=SLT-1a;
DE            Short=SLT-Ia;
DE            EC=3.2.2.22;
DE   AltName: Full=Verocytotoxin 1 subunit A;
DE   AltName: Full=Verotoxin 1 subunit A;
DE   AltName: Full=rRNA N-glycosidase 1;
DE   Flags: Precursor;
GN   Name=stxA; Synonyms=sltA;
OS   Enterobacteria phage H19B (Bacteriophage H19B).
OC   Viruses; Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes;
OC   Caudovirales; Siphoviridae; Lambdavirus; unclassified Lambdavirus.
OX   NCBI_TaxID=69932;
OH   NCBI_TaxID=562; Escherichia coli.
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=3299365; DOI=10.1073/pnas.84.13.4364;
RA   Calderwood S.B., Auclair F., Donohue-Rolfe A., Keusch G.T., Mekalanos J.J.;
RT   "Nucleotide sequence of the Shiga-like toxin genes of Escherichia coli.";
RL   Proc. Natl. Acad. Sci. U.S.A. 84:4364-4368(1987).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=3040689; DOI=10.1128/jb.169.9.4313-4319.1987;
RA   de Grandis S., Ginsberg J., Toone M., Climie S., Friesen J., Brunton J.L.;
RT   "Nucleotide sequence and promoter mapping of the Escherichia coli Shiga-
RT   like toxin operon of bacteriophage H-19B.";
RL   J. Bacteriol. 169:4313-4319(1987).
RN   [3]
RP   ACTIVE SITE.
RX   PubMed=3357883; DOI=10.1073/pnas.85.8.2568;
RA   Hovde C.J., Calderwood S.B., Mekalanos J.J., Collier R.J.;
RT   "Evidence that glutamic acid 167 is an active-site residue of Shiga-like
RT   toxin I.";
RL   Proc. Natl. Acad. Sci. U.S.A. 85:2568-2572(1988).
RN   [4]
RP   ROLE OF A2 FRAGMENT IN HOLOTOXIN ASSEMBLY.
RX   PubMed=8168939; DOI=10.1128/iai.62.5.1768-1775.1994;
RA   Austin P.R., Jablonski P.E., Bohach G.A., Dunker A.K., Hovde C.J.;
RT   "Evidence that the A2 fragment of Shiga-like toxin type I is required for
RT   holotoxin integrity.";
RL   Infect. Immun. 62:1768-1775(1994).
CC   -!- FUNCTION: The A subunit is responsible for inhibiting protein synthesis
CC       through the catalytic inactivation of 60S ribosomal subunits. After
CC       endocytosis, the A subunit is cleaved by furin in two fragments, A1 and
CC       A2: A1 is the catalytically active fragment, and A2 is essential for
CC       holotoxin assembly with the B subunits.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=Endohydrolysis of the N-glycosidic bond at one specific
CC         adenosine on the 28S rRNA.; EC=3.2.2.22;
CC   -!- SUBUNIT: Shiga-like toxin contains a single subunit A and five copies
CC       of subunit B.
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- SIMILARITY: Belongs to the ribosome-inactivating protein family.
CC       {ECO:0000305}.
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DR   EMBL; M16625; AAA98099.1; -; Genomic_DNA.
DR   EMBL; M17358; AAA32229.1; -; Genomic_DNA.
DR   PIR; A27052; XUBPH9.
DR   PIR; A53887; A53887.
DR   SMR; P08026; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0030598; F:rRNA N-glycosylase activity; IEA:UniProtKB-EC.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   GO; GO:0098676; P:modulation of host virulence by virus; IEA:UniProtKB-KW.
DR   GO; GO:0017148; P:negative regulation of translation; IEA:UniProtKB-KW.
DR   Gene3D; 3.40.420.10; -; 1.
DR   Gene3D; 4.10.470.10; -; 1.
DR   InterPro; IPR036041; Ribosome-inact_prot_sf.
DR   InterPro; IPR001574; Ribosome_inactivat_prot.
DR   InterPro; IPR017988; Ribosome_inactivat_prot_CS.
DR   InterPro; IPR016138; Ribosome_inactivat_prot_sub1.
DR   InterPro; IPR016139; Ribosome_inactivat_prot_sub2.
DR   InterPro; IPR016331; Shiga-like_toxin_subunit_A.
DR   Pfam; PF00161; RIP; 1.
DR   PIRSF; PIRSF001924; Shigella_toxin_subunit_A; 1.
DR   SUPFAM; SSF56371; SSF56371; 1.
DR   PROSITE; PS00275; SHIGA_RICIN; 1.
PE   3: Inferred from homology;
KW   Disulfide bond; Hydrolase; Modulation of host virulence by virus;
KW   Protein synthesis inhibitor; Secreted; Signal; Toxin; Viral exotoxin;
KW   Virulence.
FT   SIGNAL          1..22
FT   CHAIN           23..315
FT                   /note="Shiga-like toxin 1 subunit A"
FT                   /id="PRO_0000030791"
FT   REGION          23..273
FT                   /note="A1"
FT                   /evidence="ECO:0000250"
FT   REGION          274..315
FT                   /note="A2"
FT                   /evidence="ECO:0000250"
FT   ACT_SITE        189
FT                   /evidence="ECO:0000269|PubMed:3357883"
FT   SITE            273..274
FT                   /note="Cleavage; by furin"
FT                   /evidence="ECO:0000250"
FT   DISULFID        264..283
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   315 AA;  34800 MW;  8B993DF7A8E58F30 CRC64;
     MKIIIFRVLT FFFVIFSVNV VAKEFTLDFS TAKTYVDSLN VIRSAIGTPL QTISSGGTSL
     LMIDSGSGDN LFAVDVRGID PEEGRFNNLR LIVERNNLYV TGFVNRTNNV FYRFADFSHV
     TFPGTTAVTL SGDSSYTTLQ RVAGISRTGM QINRHSLTTS YLDLMSHSGT SLTQSVARAM
     LRFVTVTAEA LRFRQIQRGF RTTLDDLSGR SYVMTAEDVD LTLNWGRLSS VLPDYHGQDS
     VRVGRISFGS INAILGSVAL ILNCHHHASR VARMASDEFP SMCPADGRVR GITHNKILWD
     SSTLGAILMR RTISS