ID   KA26U_MESMA             Reviewed;          58 AA.
AC   P0DL65;
DT   18-JAN-2017, integrated into UniProtKB/Swiss-Prot.
DT   18-JAN-2017, sequence version 1.
DT   25-MAY-2022, entry version 15.
DE   RecName: Full=Mesomartoxin {ECO:0000303|PubMed:25514171};
DE            Short=MMTX {ECO:0000303|PubMed:25514171};
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 [MRNA], FUNCTION, STRUCTURE BY NMR OF 30-58, DISULFIDE
RP   BOND, AND SITES LYS-48 AND TYR-57.
RC   TISSUE=Venom gland;
RX   PubMed=25514171; DOI=10.1016/j.bcp.2014.12.002;
RA   Wang X., Umetsu Y., Gao B., Ohki S., Zhu S.;
RT   "Mesomartoxin, a new K(v)1.2-selective scorpion toxin interacting with the
RT   channel selectivity filter.";
RL   Biochem. Pharmacol. 93:232-239(2015).
CC   -!- FUNCTION: Recombinant toxin that reversibly blocks the voltage-gated
CC       potassium channels Shaker (IC(50)=0.054 nM), rKv1.2/KCNA2 (IC(50)=15.6
CC       nM), and rKv1.3/KCNA3 (IC(50)=12.5 uM). {ECO:0000269|PubMed:25514171}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000250}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:25514171}.
CC   -!- DOMAIN: Has the structural arrangement of an alpha-helix connected to a
CC       beta-sheet by disulfide bonds (CSalpha/beta).
CC       {ECO:0000305|PubMed:25514171}.
CC   -!- MISCELLANEOUS: Does not block the potassium channel rKv1.1/KCNA1, even
CC       at 50 uM. {ECO:0000269|PubMed:25514171}.
CC   -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC       channel inhibitor family. Alpha-KTx 26 subfamily. {ECO:0000305}.
CC   -!- WEB RESOURCE: Name=Biological Magnetic Resonance Data Bank;
CC       Note=recombinant MMTX;
CC       URL="http://www.bmrb.wisc.edu/data_library/summary/index.php?bmrbId=11536";
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DR   PDB; 2RTZ; NMR; -; A=30-58.
DR   PDBsum; 2RTZ; -.
DR   AlphaFoldDB; P0DL65; -.
DR   SMR; P0DL65; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0015459; F:potassium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   Gene3D; 3.30.30.10; -; 1.
DR   InterPro; IPR036574; Scorpion_toxin-like_sf.
DR   SUPFAM; SSF57095; SSF57095; 1.
DR   PROSITE; PS01138; SCORP_SHORT_TOXIN; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Disulfide bond; Ion channel impairing toxin;
KW   Potassium channel impairing toxin; Secreted; Signal; Toxin;
KW   Voltage-gated potassium channel impairing toxin.
FT   SIGNAL          1..29
FT                   /evidence="ECO:0000303|PubMed:25514171"
FT   PEPTIDE         30..58
FT                   /note="Mesomartoxin"
FT                   /id="PRO_0000438646"
FT   SITE            48
FT                   /note="Basic residue of the functional dyad; when
FT                   mesomartoxin-rKv1.2/KCNA2 interaction is modeled, the side
FT                   chain of this residue is plugged into the pore region of
FT                   the channel"
FT                   /evidence="ECO:0000305|PubMed:25514171"
FT   SITE            57
FT                   /note="Aromatic residue of the functional dyad; when
FT                   mesomartoxin-rKv1.2/KCNA2 interaction is modeled, this
FT                   residue is close to the Val-381 residue of the channel"
FT                   /evidence="ECO:0000269|PubMed:25514171"
FT   DISULFID        31..49
FT                   /evidence="ECO:0000269|PubMed:25514171,
FT                   ECO:0000312|PDB:2RTZ"
FT   DISULFID        35..54
FT                   /evidence="ECO:0000269|PubMed:25514171,
FT                   ECO:0000312|PDB:2RTZ"
FT   DISULFID        39..56
FT                   /evidence="ECO:0000269|PubMed:25514171,
FT                   ECO:0000312|PDB:2RTZ"
SQ   SEQUENCE   58 AA;  6502 MW;  9270B12424D84128 CRC64;
     MMSRLSVFIL IALVLSVIID VLNNSKVEGA CVENCRKYCQ DKGARNGKCI NSNCHCYY