ID   3SA5_NAJMO              Reviewed;          60 AA.
AC   P25517;
DT   01-MAY-1992, integrated into UniProtKB/Swiss-Prot.
DT   25-NOV-2002, sequence version 3.
DT   03-AUG-2022, entry version 90.
DE   RecName: Full=Cytotoxin 5;
DE   AltName: Full=CTX M5 {ECO:0000303|PubMed:8182052};
DE   AltName: Full=CTX V;
OS   Naja mossambica (Mozambique spitting cobra).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Elapinae; Naja.
OX   NCBI_TaxID=8644;
RN   [1]
RP   PROTEIN SEQUENCE, SUBCELLULAR LOCATION, AND TOXIC DOSE.
RC   TISSUE=Venom;
RX   PubMed=6353198; DOI=10.1007/bf00229242;
RA   Bougis P.E., Tessier M., van Rietschoten J., Rochat H., Faucon J.F.,
RA   Dufourcq J.;
RT   "Are interactions with phospholipids responsible for pharmacological
RT   activities of cardiotoxins?";
RL   Mol. Cell. Biochem. 55:49-64(1983).
RN   [2]
RP   FUNCTION, AND APPARTENANCE TO P-TYPE CYTOTOXIN GROUP.
RX   PubMed=8182052; DOI=10.1016/s0021-9258(17)36647-4;
RA   Chien K.-Y., Chiang C.-M., Hseu Y.-C., Vyas A.A., Rule G.S., Wu W.-G.;
RT   "Two distinct types of cardiotoxin as revealed by the structure and
RT   activity relationship of their interaction with zwitterionic phospholipid
RT   dispersions.";
RL   J. Biol. Chem. 269:14473-14483(1994).
CC   -!- FUNCTION: Shows cytolytic activity on many different cells by forming
CC       pore in lipid membranes (PubMed:8182052). In vivo, increases heart rate
CC       or kills the animal by cardiac arrest. In addition, it binds to heparin
CC       with high affinity, interacts with Kv channel-interacting protein 1
CC       (KCNIP1) in a calcium-independent manner, and binds to integrin alpha-
CC       V/beta-3 (ITGAV/ITGB3) with moderate affinity.
CC       {ECO:0000250|UniProtKB:P60301, ECO:0000250|UniProtKB:P60304,
CC       ECO:0000269|PubMed:8182052}.
CC   -!- SUBUNIT: Monomer in solution; Homodimer and oligomer in the presence of
CC       negatively charged lipids forming a pore with a size ranging between 20
CC       and 30 Angstroms. {ECO:0000250|UniProtKB:P60301}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:6353198}. Target
CC       cell membrane {ECO:0000250|UniProtKB:P60301}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- TOXIC DOSE: LD(50) is 2.85 mg/kg by intravenous injection.
CC       {ECO:0000269|PubMed:6353198}.
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|PubMed:8182052}.
CC   -!- SIMILARITY: Belongs to the snake three-finger toxin family. Short-chain
CC       subfamily. Type IA cytotoxin sub-subfamily. {ECO:0000305}.
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DR   AlphaFoldDB; P25517; -.
DR   SMR; P25517; -.
DR   PRIDE; P25517; -.
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   CDD; cd00206; snake_toxin; 1.
DR   Gene3D; 2.10.60.10; -; 1.
DR   InterPro; IPR003572; Cytotoxin_Cobra.
DR   InterPro; IPR003571; Snake_3FTx.
DR   InterPro; IPR045860; Snake_toxin-like_sf.
DR   InterPro; IPR018354; Snake_toxin_con_site.
DR   PRINTS; PR00282; CYTOTOXIN.
DR   SUPFAM; SSF57302; SSF57302; 1.
DR   PROSITE; PS00272; SNAKE_TOXIN; 1.
PE   1: Evidence at protein level;
KW   Cardiotoxin; Cytolysis; Direct protein sequencing; Disulfide bond;
KW   Membrane; Secreted; Target cell membrane; Target membrane; Toxin.
FT   CHAIN           1..60
FT                   /note="Cytotoxin 5"
FT                   /evidence="ECO:0000269|PubMed:6353198"
FT                   /id="PRO_0000093509"
FT   DISULFID        3..21
FT                   /evidence="ECO:0000250|UniProtKB:P60301"
FT   DISULFID        14..38
FT                   /evidence="ECO:0000250|UniProtKB:P60301"
FT   DISULFID        42..53
FT                   /evidence="ECO:0000250|UniProtKB:P60301"
FT   DISULFID        54..59
FT                   /evidence="ECO:0000250|UniProtKB:P60301"
SQ   SEQUENCE   60 AA;  6845 MW;  C7CBE306CC1BC8FD CRC64;
     LKCKKLIPLF SKTCPEGKNL CYKMTMRLAP KVPVKRGCID VCPKSSFLVK YECCDTDRCN