K1B1_OULSP
ID K1B1_OULSP Reviewed; 79 AA.
AC A0A330KW27;
DT 13-NOV-2019, integrated into UniProtKB/Swiss-Prot.
DT 10-OCT-2018, sequence version 1.
DT 25-MAY-2022, entry version 14.
DE RecName: Full=U-actitoxin-Oulsp1 {ECO:0000305|Ref.1};
DE Short=U-AITX-Oulsp1 {ECO:0000303|Ref.1};
DE AltName: Full=OspTx2a {ECO:0000303|Ref.1};
DE Flags: Precursor;
OS Oulactis sp. (Sea anemone).
OC Eukaryota; Metazoa; Cnidaria; Anthozoa; Hexacorallia; Actiniaria;
OC Actiniidae; Oulactis; unclassified Oulactis.
OX NCBI_TaxID=2093647;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA], SYNTHESIS OF 44-79, FUNCTION, STRUCTURE BY NMR
RP OF 44-79, AND DISULFIDE BOND.
RC STRAIN=MM-2018;
RX DOI=10.1002/pep2.24073;
RA Sunanda P., Krishnarjuna B., Peigneur S., Mitchell M.L., Estrada R.,
RA Villegas-Moreno J., Pennington M.W., Tytgat J., Norton R.S.;
RT "Identification, chemical synthesis, structure, and function of a new KV1
RT channel blocking peptide from Oulactis sp.";
RL Pept. Sci. 110:1-10(2018).
CC -!- FUNCTION: Toxin that weakly blocks two voltage-gated potassium channels
CC (IC(50)=1.8-2.5 uM on Kv1.2/KCNA2 and IC(50)=5.6-6.2 uM on
CC Kv1.6/KCNA6). {ECO:0000269|Ref.1}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305|Ref.1}. Nematocyst
CC {ECO:0000305|Ref.1}.
CC -!- PTM: Two similar peptides (OspTx2a-p1 and -p2) are obtained after
CC synthesis and oxidative folding. They may differ by a D-Cys at position
CC 76 (corresponding to OspTx2a-p2). Since C-terminal Cys residues are
CC prone to racemization during solid-phase peptide synthesis, and if the
CC presence of a D-amino acid is correct, it is probable that OspTx2a-p1
CC (L-Cys-76 form) corresponds to the native peptide. {ECO:0000305|Ref.1}.
CC -!- MISCELLANEOUS: The 49-Phe-Pro-50 bond exists only in the trans-
CC isomerization. {ECO:0000269|Ref.1}.
CC -!- MISCELLANEOUS: Has no effect on rKv1.1/KCNA1, hKv1.3/KCNA3,
CC rKv1.4/KCNA4, rKv1.5/KCNA5, hKv2.1/KCNB1, rKv3.1/KCNC1, rKv4.2/KCND2,
CC hKv10.1/EAG1/KCNH1, Kv11.1/HERG/KCNH2, and Shaker IR (tested at 10 uM).
CC {ECO:0000269|Ref.1}.
CC -!- SIMILARITY: Belongs to the sea anemone type 1 potassium channel toxin
CC family. Type 1b subfamily. {ECO:0000305}.
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DR EMBL; LT985996; SPF25670.1; -; mRNA.
DR PDB; 6CKD; NMR; -; A=44-79.
DR PDB; 6CKF; NMR; -; A=44-79.
DR PDBsum; 6CKD; -.
DR PDBsum; 6CKF; -.
DR AlphaFoldDB; A0A330KW27; -.
DR BMRB; A0A330KW27; -.
DR SMR; A0A330KW27; -.
DR GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR GO; GO:0042151; C:nematocyst; 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 InterPro; IPR003582; ShKT_dom.
DR PROSITE; PS51670; SHKT; 1.
PE 1: Evidence at protein level;
KW 3D-structure; Cleavage on pair of basic residues; Disulfide bond;
KW Ion channel impairing toxin; Nematocyst; Neurotoxin;
KW Potassium channel impairing toxin; Secreted; Signal; Toxin;
KW Voltage-gated potassium channel impairing toxin.
FT SIGNAL 1..21
FT /evidence="ECO:0000255"
FT PROPEP 22..43
FT /evidence="ECO:0000305|Ref.1"
FT /id="PRO_0000448544"
FT CHAIN 44..79
FT /note="U-actitoxin-Oulsp1"
FT /evidence="ECO:0000305|Ref.1"
FT /id="PRO_5016253688"
FT DOMAIN 45..79
FT /note="ShKT"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01005"
FT REGION 67..68
FT /note="Crucial for binding to potassium channels"
FT /evidence="ECO:0000250|UniProtKB:P29186"
FT DISULFID 45..79
FT /evidence="ECO:0000269|Ref.1, ECO:0007744|PDB:6CKF"
FT DISULFID 54..72
FT /evidence="ECO:0000269|Ref.1, ECO:0007744|PDB:6CKF"
FT DISULFID 63..76
FT /evidence="ECO:0000269|Ref.1, ECO:0007744|PDB:6CKF"
FT HELIX 51..60
FT /evidence="ECO:0007829|PDB:6CKF"
FT HELIX 62..64
FT /evidence="ECO:0007829|PDB:6CKF"
FT TURN 67..69
FT /evidence="ECO:0007829|PDB:6CKF"
FT STRAND 70..72
FT /evidence="ECO:0007829|PDB:6CKF"
FT TURN 73..77
FT /evidence="ECO:0007829|PDB:6CKF"
SQ SEQUENCE 79 AA; 8711 MW; 4C48BD7F9E5B7D9B CRC64;
MNTKLVVVFL LSAILFVSVT ASRPGKDLER DEAYETYDDE NKRACKDVFP AATCRHAKSV
GNCSSEKYKR NCAITCGAC
