ACTP3_HETMG
ID ACTP3_HETMG Reviewed; 211 AA.
AC Q9U6X1;
DT 31-JAN-2002, integrated into UniProtKB/Swiss-Prot.
DT 01-MAY-2000, sequence version 1.
DT 03-AUG-2022, entry version 94.
DE RecName: Full=DELTA-stichotoxin-Hmg2a {ECO:0000303|PubMed:22683676};
DE Short=DELTA-SHTX-Hmg2a {ECO:0000303|PubMed:22683676};
DE AltName: Full=Cytolysin III;
DE AltName: Full=Cytolysin-3;
DE AltName: Full=HMg III {ECO:0000303|PubMed:10719170};
DE Short=HMgIII {ECO:0000303|PubMed:10719170};
DE AltName: Full=Magnificalysin III {ECO:0000305|PubMed:10719170};
DE Flags: Precursor;
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 NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 35-75, AND FUNCTION.
RX PubMed=10719170; DOI=10.1016/s0167-4838(99)00289-7;
RA Wang Y., Chua K.L., Khoo H.E.;
RT "A new cytolysin from the sea anemone, Heteractis magnifica: isolation,
RT cDNA cloning and functional expression.";
RL Biochim. Biophys. Acta 1478:9-18(2000).
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).
RN [3]
RP NOMENCLATURE.
RX PubMed=22683676; DOI=10.1016/j.toxicon.2012.05.020;
RA Oliveira J.S., Fuentes-Silva D., King G.F.;
RT "Development of a rational nomenclature for naming peptide and protein
RT toxins from sea anemones.";
RL Toxicon 60:539-550(2012).
CC -!- FUNCTION: Pore-forming protein that forms cations-selective hydrophilic
CC pores of around 1 nm and causes cardiac stimulation and hemolysis. Pore
CC formation is a multi-step process that involves specific recognition of
CC membrane sphingomyelin (but neither cholesterol nor
CC phosphatidylcholine) using aromatic rich region and adjacent
CC phosphocholine (POC) binding site, firm binding to the membrane (mainly
CC driven by hydrophobic interactions) accompanied by the transfer of the
CC N-terminal region to the lipid-water interface and finally pore
CC formation after oligomerization of monomers.
CC {ECO:0000269|PubMed:10719170}.
CC -!- SUBUNIT: Tetramer in the presence of a lipidic interface. Monomer, in
CC soluble state. {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 -!- SIMILARITY: Belongs to the actinoporin family. Sea anemone subfamily.
CC {ECO:0000305}.
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DR EMBL; AF170706; AAF06362.1; -; mRNA.
DR AlphaFoldDB; Q9U6X1; -.
DR SMR; Q9U6X1; -.
DR GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR GO; GO:0042151; C:nematocyst; IEA:UniProtKB-SubCell.
DR GO; GO:0046930; C:pore complex; IEA:InterPro.
DR GO; GO:0015267; F:channel activity; IEA:InterPro.
DR GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR GO; GO:0006812; P:cation transport; IEA:InterPro.
DR GO; GO:0044179; P:hemolysis in another organism; IEA:UniProtKB-KW.
DR GO; GO:0046931; P:pore complex assembly; IEA:InterPro.
DR Gene3D; 2.60.270.20; -; 1.
DR InterPro; IPR009104; Anemon_actinoporin-like.
DR InterPro; IPR015926; Cytolysin/lectin.
DR Pfam; PF06369; Anemone_cytotox; 1.
DR SUPFAM; SSF63724; SSF63724; 1.
PE 1: Evidence at protein level;
KW Cleavage on pair of basic residues; Cytolysis; Direct protein sequencing;
KW Hemolysis; Ion transport; Membrane; Nematocyst; Secreted; Signal;
KW Target cell membrane; Target membrane; Toxin; Transmembrane; Transport.
FT SIGNAL 1..19
FT /evidence="ECO:0000255"
FT PROPEP 20..34
FT /evidence="ECO:0000269|PubMed:10719170"
FT /id="PRO_0000034840"
FT CHAIN 35..211
FT /note="DELTA-stichotoxin-Hmg2a"
FT /id="PRO_0000034841"
FT REGION 37..46
FT /note="Plays an important role in the hemolytic activity"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT REGION 45..64
FT /note="N-terminal region"
FT /evidence="ECO:0000250|UniProtKB:P61914"
FT REGION 139..154
FT /note="Trp-rich region, which is important for the binding
FT to lipid membrane"
FT /evidence="ECO:0000250|UniProtKB:P61914"
FT MOTIF 177..179
FT /note="Cell attachment site"
FT /evidence="ECO:0000255"
FT BINDING 88
FT /ligand="phosphocholine"
FT /ligand_id="ChEBI:CHEBI:295975"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT BINDING 121
FT /ligand="phosphocholine"
FT /ligand_id="ChEBI:CHEBI:295975"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT BINDING 139
FT /ligand="phosphocholine"
FT /ligand_id="ChEBI:CHEBI:295975"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT BINDING 141
FT /ligand="phosphocholine"
FT /ligand_id="ChEBI:CHEBI:295975"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT BINDING 167
FT /ligand="phosphocholine"
FT /ligand_id="ChEBI:CHEBI:295975"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT BINDING 171
FT /ligand="phosphocholine"
FT /ligand_id="ChEBI:CHEBI:295975"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT BINDING 172
FT /ligand="phosphocholine"
FT /ligand_id="ChEBI:CHEBI:295975"
FT /evidence="ECO:0000250|UniProtKB:P07845"
FT SITE 147
FT /note="Important in the initial contact with the lipid
FT membrane"
FT /evidence="ECO:0000250|UniProtKB:P61914"
FT SITE 177
FT /note="Interacts with the lipid membrane"
FT /evidence="ECO:0000250"
SQ SEQUENCE 211 AA; 23411 MW; FEC5A5B326F69110 CRC64;
MNRLIVLFLI VTMICATIAV PSREELEDQK EYKRSAALAG TIIEGASLGF QILDKVLGEL
GKVSRKIAVG VDNESGGSWT ALNAYFRSGT TDVILPEFVP NQKALLYSGR KDTGPVATGA
VAAFAYYMSN GHTLGVMFSV PFDYNFYSNW WDVKVYSGKR RADQGMYEDM YYGNPYRGDN
GWHQKNLGYG LRMKGIMTSA GEAILQIRIS R
