ID   NDB42_OPIMA             Reviewed;          71 AA.
AC   Q8MTX2;
DT   01-FEB-2003, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2002, sequence version 1.
DT   25-MAY-2022, entry version 50.
DE   RecName: Full=Cytotoxic linear peptide IsCT2 {ECO:0000303|PubMed:12054688};
DE   AltName: Full=Non-disulfide-bridged peptide 4.2 {ECO:0000303|PubMed:24184590};
DE            Short=NDBP-4.2 {ECO:0000303|PubMed:24184590};
DE   AltName: Full=Non-disulfide-bridged peptide 5.3 {ECO:0000303|PubMed:16036557};
DE            Short=NDBP-5.3 {ECO:0000303|PubMed:16036557};
DE   Contains:
DE     RecName: Full=Cytotoxic linear peptide IsCT2f {ECO:0000303|PubMed:12054688};
DE   Flags: Precursor;
OS   Opisthacanthus madagascariensis (Scorpion).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Iurida; Scorpionoidea; Hemiscorpiidae; Opisthacanthus.
OX   NCBI_TaxID=167108;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 24-36, FUNCTION, MASS
RP   SPECTROMETRY, SYNTHESIS, SUBCELLULAR LOCATION, AND AMIDATION AT PHE-36.
RC   TISSUE=Venom, and Venom gland;
RX   PubMed=12054688; DOI=10.1016/s0006-291x(02)00423-0;
RA   Dai L., Corzo G., Naoki H., Andriantsiferana M., Nakajima T.;
RT   "Purification, structure-function analysis, and molecular characterization
RT   of novel linear peptides from scorpion Opisthacanthus madagascariensis.";
RL   Biochem. Biophys. Res. Commun. 293:1514-1522(2002).
RN   [2]
RP   NOMENCLATURE.
RX   PubMed=16036557; DOI=10.1080/15216540500058899;
RA   Zeng X.C., Corzo G., Hahin R.;
RT   "Scorpion venom peptides without disulfide bridges.";
RL   IUBMB Life 57:13-21(2005).
RN   [3]
RP   NOMENCLATURE.
RX   PubMed=24184590; DOI=10.1016/j.peptides.2013.10.021;
RA   Almaaytah A., Albalas Q.;
RT   "Scorpion venom peptides with no disulfide bridges: a review.";
RL   Peptides 51:35-45(2014).
CC   -!- FUNCTION: IsCT2 shows weak hemolytic activity and antibacterial
CC       activity against both Gram-positive and Gram-negative bacteria probably
CC       by forming pores in the cell membrane. IsCT2 adopts an amphipathic
CC       alpha-helical structure. {ECO:0000269|PubMed:12054688}.
CC   -!- FUNCTION: IsCT2f shows neither hemolytic, nor antibacterial activities,
CC       surely due to the fact that it cannot apply amphipathic alpha-helical
CC       structure. {ECO:0000269|PubMed:12054688}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:12054688}. Target
CC       cell membrane {ECO:0000250}. Note=Forms a helical membrane channel in
CC       the prey. {ECO:0000250}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:12054688}.
CC   -!- PTM: IsCT2F is an enzymatic proteolytic cleavage product of IsCT2 by
CC       the proteases present in the venom. {ECO:0000305|PubMed:12054688}.
CC   -!- MASS SPECTROMETRY: [Cytotoxic linear peptide IsCT2]: Mass=1463.92;
CC       Method=MALDI; Evidence={ECO:0000269|PubMed:12054688};
CC   -!- MASS SPECTROMETRY: [Cytotoxic linear peptide IsCT2f]: Mass=1204.74;
CC       Method=MALDI; Evidence={ECO:0000269|PubMed:12054688};
CC   -!- SIMILARITY: Belongs to the non-disulfide-bridged peptide (NDBP)
CC       superfamily. Short antimicrobial peptide (group 4) family.
CC       {ECO:0000305}.
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DR   EMBL; AY050522; AAL12486.1; -; mRNA.
DR   AlphaFoldDB; Q8MTX2; -.
DR   SMR; Q8MTX2; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0016020; C:membrane; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   GO; GO:0019835; P:cytolysis; IEA:UniProtKB-KW.
DR   GO; GO:0042742; P:defense response to bacterium; IEA:UniProtKB-KW.
PE   1: Evidence at protein level;
KW   Amidation; Antibiotic; Antimicrobial; Cleavage on pair of basic residues;
KW   Cytolysis; Direct protein sequencing; Membrane; Secreted; Signal;
KW   Target cell membrane; Target membrane; Toxin.
FT   SIGNAL          1..23
FT                   /evidence="ECO:0000269|PubMed:12054688"
FT   PEPTIDE         24..36
FT                   /note="Cytotoxic linear peptide IsCT2"
FT                   /evidence="ECO:0000269|PubMed:12054688"
FT                   /id="PRO_0000035359"
FT   PEPTIDE         24..34
FT                   /note="Cytotoxic linear peptide IsCT2f"
FT                   /evidence="ECO:0000269|PubMed:12054688"
FT                   /id="PRO_0000035360"
FT   PROPEP          40..71
FT                   /evidence="ECO:0000305|PubMed:12054688"
FT                   /id="PRO_0000035361"
FT   SITE            29
FT                   /note="Important for antibacterial activity, and hemolysis
FT                   activity"
FT                   /evidence="ECO:0000250"
FT   MOD_RES         36
FT                   /note="Phenylalanine amide"
FT                   /evidence="ECO:0000269|PubMed:12054688"
SQ   SEQUENCE   71 AA;  8024 MW;  AB0EEA233A437BEC CRC64;
     MKTQFAILLV ALVLFQMFAQ SEAIFGAIWN GIKSLFGRRA LNNDLDLDGL DELFDGEISQ
     ADVDFLKELM R