3NBA_BOIIR
ID 3NBA_BOIIR Reviewed; 109 AA.
AC A0S864;
DT 15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT 09-JAN-2007, sequence version 1.
DT 25-MAY-2022, entry version 57.
DE RecName: Full=Irditoxin subunit A {ECO:0000303|PubMed:18952712};
DE Short=IrTxA {ECO:0000303|PubMed:18952712};
DE Flags: Precursor;
OS Boiga irregularis (Brown tree snake).
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC Serpentes; Colubroidea; Colubridae; Colubrinae; Boiga.
OX NCBI_TaxID=92519;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 35-99, FUNCTION, SUBUNIT,
RP SUBCELLULAR LOCATION, MASS SPECTROMETRY, TOXIC DOSE, X-RAY CRYSTALLOGRAPHY
RP (1.5 ANGSTROMS) OF 35-109, PYROGLUTAMATE FORMATION AT GLN-35, AND DISULFIDE
RP BONDS.
RC TISSUE=Venom, and Venom gland;
RX PubMed=18952712; DOI=10.1096/fj.08-113555;
RA Pawlak J., Mackessy S.P., Sixberry N.M., Stura E.A., Le Du M.H., Menez R.,
RA Foo C.S., Menez A., Nirthanan S., Kini R.M.;
RT "Irditoxin, a novel covalently linked heterodimeric three-finger toxin with
RT high taxon-specific neurotoxicity.";
RL FASEB J. 23:534-545(2009).
CC -!- FUNCTION: This bird and reptile-specific postsynaptic neurotoxin
CC inhibits the chick muscle alpha-1-beta-1-gamma-delta (CHRNA1-CHRNB1-
CC CHRNG-CHNRD) nicotinic acetylcholine receptor (nAChR) 100-fold more
CC compared with the mouse receptor. In vivo, produces rapid flaccid
CC paralysis, dyspnea and increased respiratory rate in geckos. At
CC sublethal doses geckos were immobilized for up to three days and then
CC recovered. Chicks injected with lethal doses showed rapid onset of
CC inactivity, dyspnea and neck droop, and no extended paralysis with
CC survival was seen. {ECO:0000269|PubMed:18952712}.
CC -!- SUBUNIT: Heterodimer of A and B chains; disulfide-linked.
CC {ECO:0000269|PubMed:18952712}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:18952712}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC -!- MASS SPECTROMETRY: Mass=8379.56; Mass_error=0.20; Method=Electrospray;
CC Note=The measured mass is that of the reduced peptide.;
CC Evidence={ECO:0000269|PubMed:18952712};
CC -!- TOXIC DOSE: LD(50) is 0.55 mg/kg by intraperitoneal injection into
CC geckos. {ECO:0000269|PubMed:18952712}.
CC -!- TOXIC DOSE: LD(50) is 0.22 mg/kg by intraperitoneal injection into
CC chicks. {ECO:0000269|PubMed:18952712}.
CC -!- MISCELLANEOUS: IC(50) is 11.2 nM for indirectly stimulated, nerve-
CC evoked twitch responses of the chick biventer cervicis muscle
CC acetylcholine receptor channel. {ECO:0000269|PubMed:18952712}.
CC -!- MISCELLANEOUS: Is not toxic to mice at doses up to 25 ug/g (i.p.). Does
CC not inhibit mouse alpha-3-beta-2/CHRNA3-CHRNB2 and alpha-7/CHRNA7
CC nicotinic acetylcholine receptors. {ECO:0000269|PubMed:18952712}.
CC -!- SIMILARITY: Belongs to the snake three-finger toxin family. Ancestral
CC subfamily. Boigatoxin sub-subfamily. {ECO:0000305}.
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DR EMBL; DQ304538; ABC17853.1; -; mRNA.
DR PDB; 2H7Z; X-ray; 1.50 A; A=35-109.
DR PDBsum; 2H7Z; -.
DR AlphaFoldDB; A0S864; -.
DR SMR; A0S864; -.
DR EvolutionaryTrace; A0S864; -.
DR GO; GO:0005576; C:extracellular region; IDA:UniProtKB.
DR GO; GO:0030550; F:acetylcholine receptor inhibitor activity; IDA:UniProtKB.
DR GO; GO:0099106; F:ion channel regulator activity; IEA:UniProtKB-KW.
DR GO; GO:0090729; F:toxin activity; IDA:UniProtKB.
DR GO; GO:0044504; P:modulation of receptor activity in another organism; IDA:UniProtKB.
DR Gene3D; 2.10.60.10; -; 1.
DR InterPro; IPR045860; Snake_toxin-like_sf.
DR InterPro; IPR018354; Snake_toxin_con_site.
DR SUPFAM; SSF57302; SSF57302; 1.
DR PROSITE; PS00272; SNAKE_TOXIN; 1.
PE 1: Evidence at protein level;
KW 3D-structure; Acetylcholine receptor inhibiting toxin;
KW Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW Neurotoxin; Postsynaptic neurotoxin; Pyrrolidone carboxylic acid; Secreted;
KW Signal; Toxin.
FT SIGNAL 1..19
FT /evidence="ECO:0000255"
FT PROPEP 20..34
FT /evidence="ECO:0000269|PubMed:18952712"
FT /id="PRO_0000313788"
FT CHAIN 35..109
FT /note="Irditoxin subunit A"
FT /evidence="ECO:0000305|PubMed:18952712"
FT /id="PRO_5000171334"
FT MOD_RES 35
FT /note="Pyrrolidone carboxylic acid"
FT /evidence="ECO:0000269|PubMed:18952712"
FT DISULFID 44..66
FT /evidence="ECO:0000269|PubMed:18952712,
FT ECO:0000312|PDB:2H7Z"
FT DISULFID 47..55
FT /evidence="ECO:0000269|PubMed:18952712,
FT ECO:0000312|PDB:2H7Z"
FT DISULFID 61..85
FT /evidence="ECO:0000269|PubMed:18952712,
FT ECO:0000312|PDB:2H7Z"
FT DISULFID 76
FT /note="Interchain (with C-52 in Irditoxin subunit B)"
FT /evidence="ECO:0000269|PubMed:18952712,
FT ECO:0000312|PDB:2H7Z"
FT DISULFID 89..100
FT /evidence="ECO:0000269|PubMed:18952712,
FT ECO:0000312|PDB:2H7Z"
FT DISULFID 101..106
FT /evidence="ECO:0000269|PubMed:18952712,
FT ECO:0000312|PDB:2H7Z"
FT STRAND 37..40
FT /evidence="ECO:0007829|PDB:2H7Z"
FT STRAND 42..45
FT /evidence="ECO:0007829|PDB:2H7Z"
FT TURN 49..51
FT /evidence="ECO:0007829|PDB:2H7Z"
FT STRAND 58..61
FT /evidence="ECO:0007829|PDB:2H7Z"
FT STRAND 63..72
FT /evidence="ECO:0007829|PDB:2H7Z"
FT STRAND 78..88
FT /evidence="ECO:0007829|PDB:2H7Z"
FT STRAND 97..101
FT /evidence="ECO:0007829|PDB:2H7Z"
SQ SEQUENCE 109 AA; 11938 MW; D2E1E5D42E467A12 CRC64;
MKTLLLAVAV VAFVCLGSAD QLGLGRQQID WGQGQAVGPP YTLCFECNRM TSSDCSTALR
CYRGSCYTLY RPDENCELKW AVKGCAETCP TAGPNERVKC CRSPRCNDD
