A1IB1_LOXIN
ID A1IB1_LOXIN Reviewed; 306 AA.
AC B2KKV6;
DT 28-JUL-2009, integrated into UniProtKB/Swiss-Prot.
DT 10-JUN-2008, sequence version 1.
DT 03-AUG-2022, entry version 45.
DE RecName: Full=Dermonecrotic toxin LiSicTox-alphaIA2bi;
DE EC=4.6.1.- {ECO:0000250|UniProtKB:Q4ZFU2};
DE AltName: Full=Loxtox i1;
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: Precursor;
OS Loxosceles intermedia (Brown spider).
OC Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC Araneomorphae; Haplogynae; Scytodoidea; Sicariidae; Loxosceles.
OX NCBI_TaxID=58218;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA].
RC TISSUE=Venom gland;
RX PubMed=17825864; DOI=10.1016/j.toxicon.2007.07.001;
RA Kalapothakis E., Chatzaki M., Goncalves-Dornelas H., de Castro C.S.,
RA Silvestre F.G., Laborne F.V., de Moura J.F., Veiga S.S.,
RA Chavez-Olortegui C., Granier C., Barbaro K.C.;
RT "The Loxtox protein family in Loxosceles intermedia (Mello-Leitao) venom.";
RL Toxicon 50:938-946(2007).
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:0000305|PubMed:17825864}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC {ECO:0000305|PubMed:17825864}.
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 EMBL; EF535250; ABU43329.1; -; mRNA.
DR AlphaFoldDB; B2KKV6; -.
DR SMR; B2KKV6; -.
DR ArachnoServer; AS000492; Sphingomyelinase D (LiSicTox-alphaIA2bi).
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.
DR SUPFAM; SSF51695; SSF51695; 1.
PE 2: Evidence at transcript level;
KW Cytolysis; Dermonecrotic toxin; Disulfide bond; Glycoprotein; Hemolysis;
KW Lipid degradation; Lipid metabolism; Lyase; Magnesium; Metal-binding;
KW Secreted; Signal; Toxin; Zymogen.
FT SIGNAL 1..18
FT /evidence="ECO:0000255"
FT PROPEP 19..26
FT /evidence="ECO:0000250"
FT /id="PRO_0000380633"
FT CHAIN 27..306
FT /note="Dermonecrotic toxin LiSicTox-alphaIA2bi"
FT /id="PRO_0000380634"
FT ACT_SITE 38
FT /evidence="ECO:0000250|UniProtKB:Q8I914"
FT ACT_SITE 74
FT /note="Nucleophile"
FT /evidence="ECO:0000250|UniProtKB:Q8I914"
FT BINDING 58
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250|UniProtKB:Q8I914"
FT BINDING 60
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250|UniProtKB:Q8I914"
FT BINDING 118
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250|UniProtKB:Q8I914"
FT CARBOHYD 283
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT DISULFID 78..84
FT /evidence="ECO:0000250|UniProtKB:P0CE80"
FT DISULFID 80..223
FT /evidence="ECO:0000250|UniProtKB:P0CE80"
SQ SEQUENCE 306 AA; 34122 MW; 41E0757132A59D76 CRC64;
MLPYIALILV CWSVLSQAAQ TDVEGRADKR RPIWIMGHMV NAIAQIDEFV NLGANSIETD
VSFDDNANPE YTYHGVPCDC GRSCLKWENF NDFLKGLRSA TTPGNAKYQA KLILVVFDLK
TGSLYDNQAN EAGKKLAKNL LKHYWNNGNN GGRAYIVLSI PDLNHYPLIK GFKDQLTQDG
HPELMDKVGH DFSGNDAIGD VGNAYKKAGI SGHVWQSDGI TNCLLRGLDR VKQAIANRDS
GNGFINKVYY WTVDKRATTR DALDAGVDGV MTNYPDVITD VLNESAYKNK FRVASYEDNP
WETFKK
