ID   3L27_NAJNA              Reviewed;          71 AA.
AC   C0HM09;
DT   03-AUG-2022, integrated into UniProtKB/Swiss-Prot.
DT   03-AUG-2022, sequence version 1.
DT   03-AUG-2022, entry version 1.
DE   RecName: Full=Alpha-elapitoxin-Nn3a {ECO:0000303|PubMed:35418867};
DE   AltName: Full=Long neurotoxin 7 {ECO:0000305};
DE   AltName: Full=Long-chain alpha-neurotoxin Nn3a {ECO:0000303|PubMed:35418867};
OS   Naja naja (Indian cobra).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Elapinae; Naja.
OX   NCBI_TaxID=35670;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, SUBCELLULAR LOCATION, AND MASS SPECTROMETRY.
RX   PubMed=35418867; DOI=10.3389/fphar.2022.815079;
RA   Huynh T.M., Silva A., Isbister G.K., Hodgson W.C.;
RT   "Isolation and Characterization of Two Postsynaptic Neurotoxins From Indian
RT   Cobra (Naja Naja) Venom.";
RL   Front. Pharmacol. 13:815079-815079(2022).
CC   -!- FUNCTION: Nicotinic acetylcholine receptor antagonist
CC       (PubMed:35418867). Binds to muscle nicotinic acetylcholine receptor
CC       (nAChR) and inhibits acetylcholine from binding to the receptor,
CC       thereby impairing neuromuscular transmission (PubMed:35418867).
CC       Produces peripheral paralysis by blocking neuromuscular transmission at
CC       the postsynaptic site (PubMed:35418867). Induces concentration-
CC       dependent inhibition of indirect twitches and abolishes contractile
CC       responses of tissues to exogenous acetylcholine and carbachol, in the
CC       chick biventer cervicis nerve-muscle preparation at 100-300 nM (in
CC       vitro) (PubMed:35418867). Prior incubation of tissues with Indian
CC       polyvalent antivenom (1 ml/0.6 mg) prevents the neurotoxic effects at
CC       100 nM (in vitro) (PubMed:35418867). Addition of Indian polyvalent
CC       antivenom (1 ml/0.6 mg) at the t90 time point partially restores the
CC       neurotoxic effects (in vitro) (PubMed:35418867). Displays a reversible
CC       antagonism of concentration-response curves to carbachol, with a pA2 of
CC       8.17 (in vitro) (PubMed:35418867). {ECO:0000269|PubMed:35418867}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:35418867}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- MASS SPECTROMETRY: Mass=7807.5; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:35418867};
CC   -!- MISCELLANEOUS: Constitutes approximately 3% of the whole venom protein
CC       content. {ECO:0000269|PubMed:35418867}.
CC   -!- SIMILARITY: Belongs to the snake three-finger toxin family. Long-chain
CC       subfamily. Type II alpha-neurotoxin sub-subfamily. {ECO:0000305}.
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DR   Proteomes; UP000694559; Unplaced.
PE   1: Evidence at protein level;
KW   Acetylcholine receptor inhibiting toxin; Direct protein sequencing;
KW   Disulfide bond; Ion channel impairing toxin; Neurotoxin;
KW   Postsynaptic neurotoxin; Reference proteome; Secreted; Toxin.
FT   CHAIN           1..71
FT                   /note="Alpha-elapitoxin-Nn3a"
FT                   /id="PRO_0000456214"
FT   DISULFID        3..20
FT                   /evidence="ECO:0000250|UniProtKB:P25671"
FT   DISULFID        14..42
FT                   /evidence="ECO:0000250|UniProtKB:P25671"
FT   DISULFID        26..30
FT                   /evidence="ECO:0000250|UniProtKB:P25671"
FT   DISULFID        46..56
FT                   /evidence="ECO:0000250|UniProtKB:P25671"
FT   DISULFID        57..62
FT                   /evidence="ECO:0000250|UniProtKB:P25671"
SQ   SEQUENCE   71 AA;  7805 MW;  F1981E995C9269AB CRC64;
     IRCFITPDIT SKDCPNGHVC YTKTWCDGFC SIRGERVDLD GCAATCPTVT GVDIQCCSTD
     NCNPFPTRKR P