ID   3SOF3_NAJME             Reviewed;          61 AA.
AC   P01473;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   21-JUL-1986, sequence version 1.
DT   25-MAY-2022, entry version 90.
DE   RecName: Full=Cytotoxin homolog 3 {ECO:0000305};
DE   AltName: Full=Venom component 3.20 {ECO:0000303|PubMed:1175634};
OS   Naja melanoleuca (Forest cobra) (Black-lipped cobra).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Elapinae; Naja.
OX   NCBI_TaxID=8643;
RN   [1]
RP   PROTEIN SEQUENCE, TOXIC DOSE, AND SUBCELLULAR LOCATION.
RC   TISSUE=Venom;
RX   PubMed=1175634; DOI=10.1111/j.1432-1033.1975.tb02251.x;
RA   Shipolini R.A., Kissonerghis M., Banks B.E.C.;
RT   "The primary structure of a major polypeptide component from the venom of
RT   Naja melanoleuca.";
RL   Eur. J. Biochem. 56:449-454(1975).
CC   -!- FUNCTION: Has low cytotoxic activity. {ECO:0000250|UniProtKB:P14541}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:1175634}. Target
CC       cell membrane {ECO:0000250|UniProtKB:P62375}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- TOXIC DOSE: LD(50) is 12 mg/kg by intraperitoneal injection.
CC       {ECO:0000269|PubMed:1175634}.
CC   -!- MISCELLANEOUS: Is classified as a P-type cytotoxin, since a proline
CC       residue stands at position 30 (Pro-31 in standard classification).
CC       {ECO:0000305}.
CC   -!- SIMILARITY: Belongs to the snake three-finger toxin family. Short-chain
CC       subfamily. Orphan group XV sub-subfamily. {ECO:0000305}.
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DR   PIR; A01733; H3NJ3W.
DR   AlphaFoldDB; P01473; -.
DR   SMR; P01473; -.
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   CDD; cd00206; snake_toxin; 1.
DR   Gene3D; 2.10.60.10; -; 1.
DR   InterPro; IPR003572; Cytotoxin_Cobra.
DR   InterPro; IPR016054; LY6_UPA_recep-like.
DR   InterPro; IPR003571; Snake_3FTx.
DR   InterPro; IPR045860; Snake_toxin-like_sf.
DR   InterPro; IPR018354; Snake_toxin_con_site.
DR   Pfam; PF00021; UPAR_LY6; 1.
DR   PRINTS; PR00282; CYTOTOXIN.
DR   SUPFAM; SSF57302; SSF57302; 1.
DR   PROSITE; PS00272; SNAKE_TOXIN; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Membrane; Secreted;
KW   Target cell membrane; Target membrane; Toxin.
FT   CHAIN           1..61
FT                   /note="Cytotoxin homolog 3"
FT                   /evidence="ECO:0000269|PubMed:1175634"
FT                   /id="PRO_0000093504"
FT   DISULFID        3..22
FT                   /evidence="ECO:0000250|UniProtKB:P60301"
FT   DISULFID        15..39
FT                   /evidence="ECO:0000250|UniProtKB:P60301"
FT   DISULFID        43..54
FT                   /evidence="ECO:0000250|UniProtKB:P60301"
FT   DISULFID        55..60
FT                   /evidence="ECO:0000250|UniProtKB:P60301"
SQ   SEQUENCE   61 AA;  6833 MW;  68445CF23420824D CRC64;
     IKCHNTPLPF IYKTCPEGNN LCFKGTLKFP KKITYKRGCA DACPKTSALV KYVCCNTDKC
     N