A1X1_LOXRE
ID A1X1_LOXRE Reviewed; 35 AA.
AC Q7M485;
DT 24-MAY-2004, integrated into UniProtKB/Swiss-Prot.
DT 15-DEC-2003, sequence version 1.
DT 03-AUG-2022, entry version 73.
DE RecName: Full=Dermonecrotic toxin LrSicTox-alphaI-1;
DE EC=4.6.1.- {ECO:0000250|UniProtKB:Q4ZFU2};
DE AltName: Full=Mammalian toxin;
DE AltName: Full=Phospholipase D;
DE Short=PLD;
DE AltName: Full=Sphingomyelin phosphodiesterase D;
DE Short=SMD;
DE Short=SMase D;
DE Short=Sphingomyelinase D;
DE Flags: Fragment;
OS Loxosceles reclusa (Brown recluse spider).
OC Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC Araneomorphae; Haplogynae; Scytodoidea; Sicariidae; Loxosceles.
OX NCBI_TaxID=6921;
RN [1]
RP PROTEIN SEQUENCE, AND SUBCELLULAR LOCATION.
RA Cisar C.R., Fox J.W., Geren C.R.;
RT "Screening a brown recluse spider genomic library for the gene coding for
RT the mammalian toxin using an oligonucleotide probe.";
RL Toxicon 27:37-37(1989).
RN [2]
RP FUNCTION.
RX PubMed=11137541; DOI=10.1016/s0041-0101(00)00212-9;
RA Gomez H.F., Miller M.J., Waggener M.W., Lankford H.A., Warren J.S.;
RT "Antigenic cross-reactivity of venoms from medically important north
RT american Loxosceles spider species.";
RL Toxicon 39:817-824(2001).
CC -!- FUNCTION: Dermonecrotic toxins cleave the phosphodiester linkage
CC between the phosphate and headgroup of certain phospholipids
CC (sphingolipid and lysolipid substrates), forming an alcohol (often
CC choline) and a cyclic phosphate (By similarity). This toxin acts on
CC sphingomyelin (SM) (By similarity). It may also act on ceramide
CC phosphoethanolamine (CPE), lysophosphatidylcholine (LPC) and
CC lysophosphatidylethanolamine (LPE), but not on lysophosphatidylserine
CC (LPS), and lysophosphatidylglycerol (LPG) (By similarity). It acts by
CC transphosphatidylation, releasing exclusively cyclic phosphate products
CC as second products (By similarity). Induces dermonecrosis, hemolysis,
CC increased vascular permeability, edema, inflammatory response, and
CC platelet aggregation (By similarity).
CC {ECO:0000250|UniProtKB:A0A0D4WTV1, ECO:0000250|UniProtKB:P0CE80}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=an N-(acyl)-sphingosylphosphocholine = an N-(acyl)-sphingosyl-
CC 1,3-cyclic phosphate + choline; Xref=Rhea:RHEA:60652,
CC ChEBI:CHEBI:15354, ChEBI:CHEBI:64583, ChEBI:CHEBI:143892;
CC Evidence={ECO:0000250|UniProtKB:A0A0D4WTV1};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=an N-(acyl)-sphingosylphosphoethanolamine = an N-(acyl)-
CC sphingosyl-1,3-cyclic phosphate + ethanolamine; Xref=Rhea:RHEA:60648,
CC ChEBI:CHEBI:57603, ChEBI:CHEBI:143891, ChEBI:CHEBI:143892;
CC Evidence={ECO:0000250|UniProtKB:A0A0D4WTV1};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=a 1-acyl-sn-glycero-3-phosphocholine = a 1-acyl-sn-glycero-
CC 2,3-cyclic phosphate + choline; Xref=Rhea:RHEA:60700,
CC ChEBI:CHEBI:15354, ChEBI:CHEBI:58168, ChEBI:CHEBI:143947;
CC Evidence={ECO:0000250|UniProtKB:A0A0D4WTV1};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=a 1-acyl-sn-glycero-3-phosphoethanolamine = a 1-acyl-sn-
CC glycero-2,3-cyclic phosphate + ethanolamine; Xref=Rhea:RHEA:60704,
CC ChEBI:CHEBI:57603, ChEBI:CHEBI:64381, ChEBI:CHEBI:143947;
CC Evidence={ECO:0000250|UniProtKB:A0A0D4WTV1};
CC -!- COFACTOR:
CC Name=Mg(2+); Xref=ChEBI:CHEBI:18420;
CC Evidence={ECO:0000250|UniProtKB:Q8I914};
CC Note=Binds 1 Mg(2+) ion per subunit. {ECO:0000250|UniProtKB:Q8I914};
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|Ref.1}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305|Ref.1}.
CC -!- PTM: Contains 2 disulfide bonds. {ECO:0000250|UniProtKB:P0CE80}.
CC -!- SIMILARITY: Belongs to the arthropod phospholipase D family. Class II
CC subfamily. {ECO:0000305}.
CC -!- CAUTION: The most common activity assay for dermonecrotic toxins
CC detects enzymatic activity by monitoring choline release from
CC substrate. Liberation of choline from sphingomyelin (SM) or
CC lysophosphatidylcholine (LPC) is commonly assumed to result from
CC substrate hydrolysis, giving either ceramide-1-phosphate (C1P) or
CC lysophosphatidic acid (LPA), respectively, as a second product.
CC However, two studies from Lajoie and colleagues (2013 and 2015) report
CC the observation of exclusive formation of cyclic phosphate products as
CC second products, resulting from intramolecular transphosphatidylation.
CC Cyclic phosphates have vastly different biological properties from
CC their monoester counterparts, and they may be relevant to the pathology
CC of brown spider envenomation. {ECO:0000250|UniProtKB:A0A0D4WTV1,
CC ECO:0000250|UniProtKB:A0A0D4WV12, ECO:0000250|UniProtKB:Q4ZFU2}.
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DR PIR; A38107; A38107.
DR AlphaFoldDB; Q7M485; -.
DR SMR; Q7M485; -.
DR ArachnoServer; AS000160; Sphingomyelinase D (LrSicTox1) (N-terminal fragment).
DR GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR GO; GO:0016829; F:lyase activity; IEA:UniProtKB-KW.
DR GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR GO; GO:0008081; F:phosphoric diester hydrolase activity; IEA:InterPro.
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:0016042; P:lipid catabolic process; IEA:UniProtKB-KW.
DR Gene3D; 3.20.20.190; -; 1.
DR InterPro; IPR017946; PLC-like_Pdiesterase_TIM-brl.
PE 1: Evidence at protein level;
KW Cytolysis; Dermonecrotic toxin; Direct protein sequencing; Disulfide bond;
KW Hemolysis; Lipid degradation; Lipid metabolism; Lyase; Magnesium;
KW Metal-binding; Secreted; Toxin.
FT CHAIN 1..>35
FT /note="Dermonecrotic toxin LrSicTox-alphaI-1"
FT /id="PRO_0000087677"
FT ACT_SITE 11
FT /evidence="ECO:0000250|UniProtKB:Q8I914"
FT BINDING 33
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250|UniProtKB:Q8I914"
FT NON_TER 35
SQ SEQUENCE 35 AA; 3905 MW; B6EFE750E46C1AFB CRC64;
ANKRPVWIMG HMVNAVYQID EFVNLGANSI DTDVS
