ID   ACTP2_HETMG             Reviewed;          22 AA.
AC   P58690;
DT   31-JAN-2002, integrated into UniProtKB/Swiss-Prot.
DT   31-JAN-2002, sequence version 1.
DT   25-MAY-2022, entry version 65.
DE   RecName: Full=Magnificalysin II {ECO:0000303|PubMed:8146870};
DE            Short=HMg II;
DE   AltName: Full=Cytolysin II;
DE   AltName: Full=DELTA-stichotoxin {ECO:0000305};
DE   Flags: Fragment;
OS   Heteractis magnifica (Magnificent sea anemone) (Radianthus magnifica).
OC   Eukaryota; Metazoa; Cnidaria; Anthozoa; Hexacorallia; Actiniaria;
OC   Stichodactylidae; Heteractis.
OX   NCBI_TaxID=38281;
RN   [1]
RP   PROTEIN SEQUENCE, TOXIC DOSE, HEMOLYTIC ACTIVITIES, AND FUNCTION.
RX   PubMed=8146870; DOI=10.1016/0041-0101(93)90341-f;
RA   Khoo K.S., Kam W.K., Khoo H.E., Gopalakrishnakone P., Chung M.C.;
RT   "Purification and partial characterization of two cytolysins from a
RT   tropical sea anemone, Heteractis magnifica.";
RL   Toxicon 31:1567-1579(1993).
RN   [2]
RP   REVIEW.
RX   PubMed=19268680; DOI=10.1016/j.toxicon.2009.02.026;
RA   Kristan K.C., Viero G., Dalla Serra M., Macek P., Anderluh G.;
RT   "Molecular mechanism of pore formation by actinoporins.";
RL   Toxicon 54:1125-1134(2009).
CC   -!- FUNCTION: Pore-forming protein that forms cations-selective hydrophilic
CC       pores of around 1 nm and causes cytolysis. Pore formation is a multi-
CC       step process that involves specific recognition of membrane
CC       sphingomyelin (but neither cholesterol nor phosphatidylcholine) using
CC       aromatic rich region and adjacent phosphocholine (POC) binding site,
CC       firm binding to the membrane (mainly driven by hydrophobic
CC       interactions) accompanied by the transfer of the N-terminal region to
CC       the lipid-water interface and finally pore formation after
CC       oligomerization of monomers. {ECO:0000269|PubMed:8146870}.
CC   -!- SUBUNIT: Tetramer in the presence of a lipidic interface. Monomer, in
CC       soluble state (By similarity). {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Secreted. Nematocyst. Target cell membrane.
CC       Note=Forms an alpha-helical membrane channel in the prey.
CC   -!- DOMAIN: The N-terminal region, before the pore is formed, is bound to
CC       the lipid membrane. It partitions into the lipid-water interface and
CC       stabilizes the monomeric molecule on the membrane. Finally, it
CC       traverses the bilayer, thus forming the transmembrane pore.
CC       {ECO:0000250|UniProtKB:P61914}.
CC   -!- TOXIC DOSE: LD(50) is 320 ug/kg by intravenous injection into mice.
CC       {ECO:0000269|PubMed:8146870}.
CC   -!- MISCELLANEOUS: Hemolytic activity is 3.3 x 10(4) HU/mg.
CC   -!- SIMILARITY: Belongs to the actinoporin family. Sea anemone subfamily.
CC       {ECO:0000305}.
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DR   AlphaFoldDB; P58690; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0042151; C:nematocyst; IEA:UniProtKB-SubCell.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   GO; GO:0044179; P:hemolysis in another organism; IEA:UniProtKB-KW.
DR   GO; GO:0006811; P:ion transport; IEA:UniProtKB-KW.
PE   1: Evidence at protein level;
KW   Cytolysis; Direct protein sequencing; Hemolysis; Ion transport; Membrane;
KW   Nematocyst; Secreted; Target cell membrane; Target membrane; Toxin;
KW   Transmembrane; Transport.
FT   CHAIN           1..>22
FT                   /note="Magnificalysin II"
FT                   /id="PRO_0000221535"
FT   REGION          3..12
FT                   /note="Plays an important role in the hemolytic activity"
FT                   /evidence="ECO:0000250|UniProtKB:P07845"
FT   REGION          11..>22
FT                   /note="N-terminal region"
FT                   /evidence="ECO:0000250|UniProtKB:P61914"
FT   NON_TER         22
SQ   SEQUENCE   22 AA;  2146 MW;  42929378DF4AA835 CRC64;
     SAALAGTIID GASLGFDILN KV