3NBB_BOIIR
ID 3NBB_BOIIR Reviewed; 111 AA.
AC A0S865;
DT 15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT 09-JAN-2007, sequence version 1.
DT 25-MAY-2022, entry version 59.
DE RecName: Full=Irditoxin subunit B {ECO:0000303|PubMed:18952712};
DE Short=IrTxB {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 35-111, 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-CHRND) 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=8677.79; Mass_error=0.12; 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; DQ304539; ABC17854.1; -; mRNA.
DR PDB; 2H7Z; X-ray; 1.50 A; B=35-111.
DR PDBsum; 2H7Z; -.
DR AlphaFoldDB; A0S865; -.
DR SMR; A0S865; -.
DR EvolutionaryTrace; A0S865; -.
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 InterPro; IPR035076; Toxin/TOLIP.
DR Pfam; PF00087; Toxin_TOLIP; 1.
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_0000313789"
FT CHAIN 35..111
FT /note="Irditoxin subunit B"
FT /evidence="ECO:0000269|PubMed:18952712"
FT /id="PRO_5000171335"
FT MOD_RES 35
FT /note="Pyrrolidone carboxylic acid"
FT /evidence="ECO:0000269|PubMed:18952712"
FT DISULFID 44..68
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 52
FT /note="Interchain (with C-66 in Irditoxin subunit B)"
FT /evidence="ECO:0000269|PubMed:18952712,
FT ECO:0000312|PDB:2H7Z"
FT DISULFID 61..87
FT /evidence="ECO:0000269|PubMed:18952712,
FT ECO:0000312|PDB:2H7Z"
FT DISULFID 91..102
FT /evidence="ECO:0000269|PubMed:18952712,
FT ECO:0000312|PDB:2H7Z"
FT DISULFID 103..108
FT /evidence="ECO:0000269|PubMed:18952712,
FT ECO:0000312|PDB:2H7Z"
FT TURN 49..51
FT /evidence="ECO:0007829|PDB:2H7Z"
FT STRAND 67..74
FT /evidence="ECO:0007829|PDB:2H7Z"
FT STRAND 76..78
FT /evidence="ECO:0007829|PDB:2H7Z"
FT STRAND 80..90
FT /evidence="ECO:0007829|PDB:2H7Z"
FT STRAND 99..103
FT /evidence="ECO:0007829|PDB:2H7Z"
FT TURN 106..109
FT /evidence="ECO:0007829|PDB:2H7Z"
SQ SEQUENCE 111 AA; 12236 MW; 448F0CEE68E92E12 CRC64;
MKTLLLAVAV VAFVCLGSAD QLGLGRQQID WGKGQAKGPP YTLCFECNRE TCSNCFKDNR
CPPYHRTCYT LYRPDGNGEM KWAVKGCAKT CPTAQPGESV QCCNTPKCND Y
