CA1AB_CONSP
ID CA1AB_CONSP Reviewed; 69 AA.
AC P85886;
DT 05-MAY-2009, integrated into UniProtKB/Swiss-Prot.
DT 05-MAY-2009, sequence version 1.
DT 25-MAY-2022, entry version 31.
DE RecName: Full=Alpha-conotoxin SrIA/SrIB {ECO:0000303|PubMed:17635581};
DE Flags: Precursor;
OS Conus spurius (Alphabet cone).
OC Eukaryota; Metazoa; Spiralia; Lophotrochozoa; Mollusca; Gastropoda;
OC Caenogastropoda; Neogastropoda; Conoidea; Conidae; Conus; Lindaconus.
OX NCBI_TaxID=192919;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 49-66, FUNCTION,
RP SUBCELLULAR LOCATION, MASS SPECTROMETRY, GAMMA-CARBOXYGLUTAMATION AT GLU-60
RP AND GLU-63, AMIDATION AT GLY-66, HYDROXYLATION AT PRO-55, AND DISULFIDE
RP BONDS.
RC TISSUE=Venom, and Venom duct;
RX PubMed=17635581; DOI=10.1111/j.1742-4658.2007.05931.x;
RA Lopez-Vera E., Aguilar M.B., Schiavon E., Marinzi C., Ortiz E.,
RA Restano Cassulini R., Batista C.V.F., Possani L.D.,
RA Heimer de la Cotera E.P., Peri F., Becerril B., Wanke E.;
RT "Novel alpha-conotoxins from Conus spurius and the alpha-conotoxin EI share
RT high-affinity potentiation and low-affinity inhibition of nicotinic
RT acetylcholine receptors.";
RL FEBS J. 274:3972-3985(2007).
CC -!- FUNCTION: Alpha-conotoxins act on postsynaptic membranes, they bind to
CC the nicotinic acetylcholine receptors (nAChR) and thus inhibit them.
CC Has weak blocking effects on muscle nAChR composed of alpha-1/beta-
CC 1/gamma/delta subunits and the central nervous system nAChR composed of
CC alpha-4/beta-2 subunits. Does not detectably affect the peripheral
CC nervous system nAChR composed of alpha-3/beta-4 subunits. Low toxin
CC concentrations potentiate currents in muscle nAChR composed of alpha-
CC 1/beta-1/gamma/delta subunits and central nervous system nAChR composed
CC of alpha-4/beta-2 subunits, but not the peripheral nervous system nAChR
CC composed of alpha-3/beta-4 subunits. {ECO:0000269|PubMed:17635581}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:17635581}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom duct.
CC {ECO:0000305|PubMed:17635581}.
CC -!- DOMAIN: The cysteine framework is I (CC-C-C). Alpha4/7 pattern.
CC {ECO:0000305}.
CC -!- PTM: Occurs in 2 forms which differ in the post-translational
CC modification of Glu-60. In form SrA1 Glu-60 is 4-carboxyglutamate while
CC in form SrA2 Glu-60 is unmodified. {ECO:0000269|PubMed:17635581}.
CC -!- MASS SPECTROMETRY: Mass=2202.9; Method=Electrospray; Note=Conotoxin
CC Sr1A, with 4-carboxyglutamate at Glu-60.;
CC Evidence={ECO:0000269|PubMed:17635581};
CC -!- MASS SPECTROMETRY: Mass=2158.8; Method=Electrospray; Note=Conotoxin
CC Sr1B, without 4-carboxyglutamate at Glu-60.;
CC Evidence={ECO:0000269|PubMed:17635581};
CC -!- SIMILARITY: Belongs to the conotoxin A superfamily. {ECO:0000305}.
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DR AlphaFoldDB; P85886; -.
DR ConoServer; 3751; SrIA/SrIB precursor.
DR GO; GO:0005576; C:extracellular region; IDA:UniProtKB.
DR GO; GO:0035792; C:host cell postsynaptic membrane; IEA:UniProtKB-KW.
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 InterPro; IPR009958; Conotoxin_a-typ.
DR InterPro; IPR018072; Conotoxin_a-typ_CS.
DR Pfam; PF07365; Toxin_8; 1.
DR PROSITE; PS60014; ALPHA_CONOTOXIN; 1.
PE 1: Evidence at protein level;
KW Acetylcholine receptor inhibiting toxin; Amidation;
KW Direct protein sequencing; Disulfide bond; Gamma-carboxyglutamic acid;
KW Hydroxylation; Ion channel impairing toxin; Neurotoxin;
KW Postsynaptic neurotoxin; Secreted; Signal; Toxin.
FT SIGNAL 1..21
FT /evidence="ECO:0000255"
FT PROPEP 22..48
FT /evidence="ECO:0000255, ECO:0000269|PubMed:17635581"
FT /id="PRO_0000372708"
FT PEPTIDE 49..66
FT /note="Alpha-conotoxin SrIA/SrIB"
FT /evidence="ECO:0000269|PubMed:17635581"
FT /id="PRO_0000372709"
FT REGION 53..55
FT /note="Ser-Xaa-Pro motif, crucial for potent interaction
FT with nAChR"
FT /evidence="ECO:0000250|UniProtKB:P56636"
FT MOD_RES 55
FT /note="4-hydroxyproline; in form Sr1A and Sr1B"
FT /evidence="ECO:0000269|PubMed:17635581"
FT MOD_RES 60
FT /note="4-carboxyglutamate; in form Sr1A"
FT /evidence="ECO:0000269|PubMed:17635581"
FT MOD_RES 63
FT /note="4-carboxyglutamate; in form Sr1A and Sr1B"
FT /evidence="ECO:0000269|PubMed:17635581"
FT MOD_RES 66
FT /note="Glycine amide; in form Sr1A and Sr1B"
FT /evidence="ECO:0000269|PubMed:17635581"
FT DISULFID 51..57
FT /evidence="ECO:0000269|PubMed:17635581"
FT DISULFID 52..65
FT /evidence="ECO:0000269|PubMed:17635581"
SQ SEQUENCE 69 AA; 7689 MW; 5124A4B09A970576 CRC64;
MGMRMMFTVF LLVVLATTVV SFTSDSAFDS RNVAANDKVS DMIALTARRT CCSRPTCRME
YPELCGGRR
