ID   CLCA1_MESMA             Reviewed;          64 AA.
AC   Q8I6X9; Q4EW08;
DT   09-JAN-2007, integrated into UniProtKB/Swiss-Prot.
DT   20-DEC-2005, sequence version 2.
DT   25-MAY-2022, entry version 44.
DE   RecName: Full=Toxin BmCa-1;
DE   AltName: Full=BmKCaTx4 {ECO:0000303|PubMed:24129506};
DE   AltName: Full=Calcium channel toxin BmCa1;
DE   Flags: Precursor;
OS   Mesobuthus martensii (Manchurian scorpion) (Buthus martensii).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Mesobuthus.
OX   NCBI_TaxID=34649;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA / MRNA].
RC   TISSUE=Venom gland;
RX   PubMed=16298458; DOI=10.1016/j.peptides.2005.10.010;
RA   Cao Z.-J., Xie Y., Dai C., Zhu S.-Y., Yin S.-J., Wu Y.-L., Li W.-X.;
RT   "Cloning and characterization of a novel calcium channel toxin-like gene
RT   BmCa1 from Chinese scorpion Mesobuthus martensii Karsch.";
RL   Peptides 27:1235-1240(2006).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RX   PubMed=16513212; DOI=10.1016/j.peptides.2006.01.012;
RA   Zeng X.-C., Luo F., Li W.-X.;
RT   "Molecular dissection of venom from Chinese scorpion Mesobuthus martensii:
RT   identification and characterization of four novel disulfide-bridged venom
RT   peptides.";
RL   Peptides 27:1745-1754(2006).
RN   [3]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   TISSUE=Muscle;
RX   PubMed=24129506; DOI=10.1038/ncomms3602;
RA   Cao Z., Yu Y., Wu Y., Hao P., Di Z., He Y., Chen Z., Yang W., Shen Z.,
RA   He X., Sheng J., Xu X., Pan B., Feng J., Yang X., Hong W., Zhao W., Li Z.,
RA   Huang K., Li T., Kong Y., Liu H., Jiang D., Zhang B., Hu J., Hu Y.,
RA   Wang B., Dai J., Yuan B., Feng Y., Huang W., Xing X., Zhao G., Li X.,
RA   Li Y., Li W.;
RT   "The genome of Mesobuthus martensii reveals a unique adaptation model of
RT   arthropods.";
RL   Nat. Commun. 4:2602-2602(2013).
CC   -!- FUNCTION: May increase intracellular calcium release through the
CC       activation of nuclear inositol 1,4,5-trisphosphate receptors (ITPR) of
CC       cardiomyocytes, thereby causing an increase in the contraction
CC       frequency of these cells. {ECO:0000250|UniProtKB:P0DM29}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305|PubMed:16298458}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:16298458}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin.
CC       {ECO:0000250|UniProtKB:P59868}.
CC   -!- SIMILARITY: Belongs to the scorpion calcin-like family. {ECO:0000305}.
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DR   EMBL; AF419253; AAN32700.2; -; mRNA.
DR   EMBL; DQ201205; ABB83686.1; -; mRNA.
DR   EMBL; DQ206446; ABB43242.1; -; Genomic_DNA.
DR   EMBL; DQ272503; ABB85068.1; -; Genomic_DNA.
DR   EMBL; DQ120790; AAZ16270.1; -; mRNA.
DR   AlphaFoldDB; Q8I6X9; -.
DR   SMR; Q8I6X9; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0005246; F:calcium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0015459; F:potassium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
PE   3: Inferred from homology;
KW   Calcium channel impairing toxin; Disulfide bond;
KW   Ion channel impairing toxin; Knottin; Potassium channel impairing toxin;
KW   Ryanodine-sensitive calcium-release channel impairing toxin; Secreted;
KW   Signal; Toxin.
FT   SIGNAL          1..18
FT                   /evidence="ECO:0000255"
FT   PROPEP          19..27
FT                   /evidence="ECO:0000250"
FT                   /id="PRO_0000271331"
FT   CHAIN           28..64
FT                   /note="Toxin BmCa-1"
FT                   /id="PRO_5000061335"
FT   DISULFID        29..43
FT                   /evidence="ECO:0000250|UniProtKB:P59868"
FT   DISULFID        36..49
FT                   /evidence="ECO:0000250|UniProtKB:P59868"
FT   DISULFID        42..58
FT                   /evidence="ECO:0000250|UniProtKB:P59868"
FT   CONFLICT        1..7
FT                   /note="MNTFVVV -> MKS (in Ref. 2; AAZ16270)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   64 AA;  7176 MW;  8EE2C04AB033049D CRC64;
     MNTFVVVFLL LTAILCHAEH ALDETARGCN RLNKKCNSDG DCCRYGERCI STGVNYYCRP
     DFGP