ID   CYAB_AMAPH              Reviewed;          34 AA.
AC   P0CU58;
DT   28-MAR-2018, integrated into UniProtKB/Swiss-Prot.
DT   28-MAR-2018, sequence version 1.
DT   25-MAY-2022, entry version 8.
DE   RecName: Full=Cycloamanide B proprotein {ECO:0000303|PubMed:27978833};
DE   Contains:
DE     RecName: Full=Cycloamanide B {ECO:0000303|PubMed:27978833};
DE              Short=CyA B {ECO:0000303|PubMed:8441706};
DE              Short=Cyl B {ECO:0000303|PubMed:28866879};
DE   Flags: Precursor;
OS   Amanita phalloides (Death cap).
OC   Eukaryota; Fungi; Dikarya; Basidiomycota; Agaricomycotina; Agaricomycetes;
OC   Agaricomycetidae; Agaricales; Amanitaceae; Amanita.
OX   NCBI_TaxID=67723;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA], AND FUNCTION.
RX   PubMed=27978833; DOI=10.1186/s12864-016-3378-7;
RA   Pulman J.A., Childs K.L., Sgambelluri R.M., Walton J.D.;
RT   "Expansion and diversification of the MSDIN family of cyclic peptide genes
RT   in the poisonous agarics Amanita phalloides and A. bisporigera.";
RL   BMC Genomics 17:1038-1038(2016).
RN   [2]
RP   FUNCTION.
RX   PubMed=8441706; DOI=10.1016/0196-9781(93)90003-y;
RA   Wieczorek Z., Siemion I.Z., Zimecki M., Bolewska-Pedyczak E., Wieland T.;
RT   "Immunosuppressive activity in the series of cycloamanide peptides from
RT   mushrooms.";
RL   Peptides 14:1-5(1993).
RN   [3]
RP   CYCLIZATION.
RX   PubMed=28866879; DOI=10.1021/acssynbio.7b00264;
RA   Sgambelluri R.M., Smith M.O., Walton J.D.;
RT   "Versatility of prolyl oligopeptidase B in peptide macrocyclization.";
RL   ACS Synth. Biol. 7:145-152(2018).
CC   -!- FUNCTION: Cyclic heptapeptide that belongs to the MSDIN-like toxin
CC       family responsible for a large number of food poisoning cases and
CC       deaths (PubMed:27978833). Cycloaminide B is non-toxic to mammals but
CC       shows immunosuppressive activity, probably through the inhibition of
CC       the action of interleukin-1 and interleukin-2 (PubMed:27978833,
CC       PubMed:8441706). {ECO:0000269|PubMed:8441706,
CC       ECO:0000305|PubMed:27978833}.
CC   -!- PTM: Processed by the macrocyclase-peptidase enzyme POPB to yield a
CC       cyclic decapeptide (By similarity). POPB first removes 10 residues from
CC       the N-terminus (PubMed:28866879). Conformational trapping of the
CC       remaining peptide forces the enzyme to release this intermediate rather
CC       than proceed to macrocyclization (By similarity). The enzyme rebinds
CC       the remaining peptide in a different conformation and catalyzes
CC       macrocyclization of the N-terminal 7 residues (PubMed:28866879).
CC       {ECO:0000250|UniProtKB:A0A067SLB9, ECO:0000269|PubMed:28866879}.
CC   -!- SIMILARITY: Belongs to the MSDIN fungal toxin family. {ECO:0000305}.
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DR   AlphaFoldDB; P0CU58; -.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   InterPro; IPR027582; Amanitin/phalloidin.
DR   TIGRFAMs; TIGR04309; amanitin; 1.
PE   3: Inferred from homology;
KW   Toxin.
FT   PROPEP          1..10
FT                   /evidence="ECO:0000305|PubMed:27978833"
FT                   /id="PRO_0000443778"
FT   PEPTIDE         11..17
FT                   /note="Cycloamanide B"
FT                   /evidence="ECO:0000305|PubMed:27978833"
FT                   /id="PRO_0000443779"
FT   PROPEP          18..34
FT                   /evidence="ECO:0000305|PubMed:27978833"
FT                   /id="PRO_0000443780"
FT   CROSSLNK        11..17
FT                   /note="Cyclopeptide (Ser-Pro)"
FT                   /evidence="ECO:0000305|PubMed:27978833"
SQ   SEQUENCE   34 AA;  3789 MW;  D57E69725B1EAE16 CRC64;
     MSDINAARLP SFFFPIPCIS DDIEMVLTRG ESLC