A1IB2_LOXIN
ID A1IB2_LOXIN Reviewed; 302 AA.
AC B2KKV7;
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-alphaIA2bii;
DE EC=4.6.1.- {ECO:0000250|UniProtKB:Q4ZFU2};
DE AltName: Full=Loxtox i2;
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; Fragment;
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; EF535251; ABU43330.1; -; mRNA.
DR AlphaFoldDB; B2KKV7; -.
DR SMR; B2KKV7; -.
DR ArachnoServer; AS000693; Sphingomyelinase D (LiSicTox-alphaIA2bii).
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..14
FT /evidence="ECO:0000255"
FT PROPEP 15..22
FT /evidence="ECO:0000250"
FT /id="PRO_0000380635"
FT CHAIN 23..302
FT /note="Dermonecrotic toxin LiSicTox-alphaIA2bii"
FT /id="PRO_0000380636"
FT ACT_SITE 34
FT /evidence="ECO:0000250|UniProtKB:Q8I914"
FT ACT_SITE 70
FT /note="Nucleophile"
FT /evidence="ECO:0000250|UniProtKB:Q8I914"
FT BINDING 54
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250|UniProtKB:Q8I914"
FT BINDING 56
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250|UniProtKB:Q8I914"
FT BINDING 114
FT /ligand="Mg(2+)"
FT /ligand_id="ChEBI:CHEBI:18420"
FT /evidence="ECO:0000250|UniProtKB:Q8I914"
FT CARBOHYD 279
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT DISULFID 74..80
FT /evidence="ECO:0000250|UniProtKB:P0CE80"
FT DISULFID 76..219
FT /evidence="ECO:0000250|UniProtKB:P0CE80"
FT NON_TER 1
SQ SEQUENCE 302 AA; 33627 MW; 871758A6434036F4 CRC64;
IALILVCWSV LSQAAQTDVE GRADKRRPIW IMGHMVNAIA QIDEFVNLGA NSIETDVSFD
DNANPEYTYH GVPCDCGRSC LKWENFNDFL KGLRSATTPG NAKYQAKLIL VVFDLKTGSL
YDNQANEAGK KLAKNLLKHY WNNGNNGGRA YIVLSIPDLN HYPLIKGFKD QLTHDGHPEL
MDKVGHDFSG NDAIGDVGNA YKKAGISGHV WQSDGITNCL LRGLDRVKQA IANRDSGNGF
INKVYYWTVD KRATTRDALD AGVDGVMTNY PDVITDVLNE SAYKNKFRVA SYEDNPWETF
KK
