PA2B_OPHSH
ID PA2B_OPHSH Reviewed; 107 AA.
AC C0HLF7;
DT 16-JAN-2019, integrated into UniProtKB/Swiss-Prot.
DT 16-JAN-2019, sequence version 1.
DT 03-AUG-2022, entry version 10.
DE RecName: Full=Basic phospholipase A2 sphenotoxin subunit B {ECO:0000303|PubMed:30205237};
DE Short=svPLA2;
DE EC=3.1.1.4 {ECO:0000255|PROSITE-ProRule:PRU10035, ECO:0000269|PubMed:30205237};
DE AltName: Full=Phosphatidylcholine 2-acylhydrolase;
DE Flags: Fragments;
OS Ophryacus sphenophrys (Broad-horned pitviper) (Bothrops sphenophrys).
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC Serpentes; Colubroidea; Viperidae; Crotalinae; Ophryacus.
OX NCBI_TaxID=2340898;
RN [1]
RP PROTEIN SEQUENCE, FUNCTION, SUBUNIT, SUBCELLULAR LOCATION, AND MASS
RP SPECTROMETRY.
RC STRAIN=Mexico; TISSUE=Venom;
RX PubMed=30205237; DOI=10.1016/j.jprot.2018.09.002;
RA Neri-Castro E., Lomonte B., Valdes M., Ponce-Lopez R., Benard-Valle M.,
RA Borja M., Strickland J.L., Jones J.M., Gruenwald C., Zamudio F., Alagon A.;
RT "Venom characterization of the three species of Ophryacus and proteomic
RT profiling of O. sphenophrys unveils Sphenotoxin, a novel Crotoxin-like
RT heterodimeric beta-neurotoxin.";
RL J. Proteomics 192:196-207(2019).
CC -!- FUNCTION: Heterodimer A-B: Sphenotoxin is a potent neurotoxin that
CC possesses phospholipase A2 (PLA2) activity. It consists of a non-
CC covalent association of a basic PLA2 subunit B with a non-enzymatic
CC subunit A. {ECO:0000269|PubMed:30205237}.
CC -!- FUNCTION: Monomer B: Not found in vivo. In vitro, potent neurotoxin
CC that possesses phospholipase A2 (PLA2) activity and exerts a lethal
CC action by blocking neuromuscular transmission. Induces paralysis of the
CC hind legs and neuromuscular blockade in mouse phrenic nerve-diaphragm
CC preparations. PLA2 catalyzes the calcium-dependent hydrolysis of the 2-
CC acyl groups in 3-sn-phosphoglycerides. {ECO:0000269|PubMed:30205237}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=a 1,2-diacyl-sn-glycero-3-phosphocholine + H2O = a 1-acyl-sn-
CC glycero-3-phosphocholine + a fatty acid + H(+); Xref=Rhea:RHEA:15801,
CC ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:28868,
CC ChEBI:CHEBI:57643, ChEBI:CHEBI:58168; EC=3.1.1.4;
CC Evidence={ECO:0000255|PROSITE-ProRule:PRU10035,
CC ECO:0000269|PubMed:30205237};
CC -!- SUBUNIT: Heterodimer of A and B chains; non-covalently linked. The
CC acidic protein (B chain) has phospholipase A2 activity and the A chain
CC weakly inhibits the B chain enzymatic activity but potentiates its
CC lethal potency. {ECO:0000269|PubMed:30205237}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:30205237}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC {ECO:0000305|PubMed:30205237}.
CC -!- MASS SPECTROMETRY: Mass=14264; Method=Electrospray;
CC Evidence={ECO:0000269|PubMed:30205237};
CC -!- TOXIC DOSE: In monomer B, LD(50) is 0.49 ug/g by intravenous injection
CC into mice. Toxicity is higher in combination with subunit A.
CC {ECO:0000269|PubMed:30205237}.
CC -!- TOXIC DOSE: In heterodimer A-B, LD(50) is 0.16 ug/g by intravenous
CC injection into mice. {ECO:0000269|PubMed:30205237}.
CC -!- SIMILARITY: Belongs to the phospholipase A2 family. Group II subfamily.
CC D49 sub-subfamily. {ECO:0000305}.
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DR AlphaFoldDB; C0HLF7; -.
DR SMR; C0HLF7; -.
DR GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR GO; GO:0005509; F:calcium ion binding; IEA:InterPro.
DR GO; GO:0004623; F:phospholipase A2 activity; IEA:UniProtKB-EC.
DR GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR GO; GO:0050482; P:arachidonic acid secretion; IEA:InterPro.
DR GO; GO:0016042; P:lipid catabolic process; IEA:UniProtKB-KW.
DR GO; GO:0006644; P:phospholipid metabolic process; IEA:InterPro.
DR CDD; cd00125; PLA2c; 1.
DR Gene3D; 1.20.90.10; -; 1.
DR InterPro; IPR001211; PLipase_A2.
DR InterPro; IPR016090; PLipase_A2_dom.
DR InterPro; IPR036444; PLipase_A2_dom_sf.
DR InterPro; IPR033113; PLipase_A2_His_AS.
DR PANTHER; PTHR11716; PTHR11716; 1.
DR Pfam; PF00068; Phospholip_A2_1; 1.
DR PRINTS; PR00389; PHPHLIPASEA2.
DR SMART; SM00085; PA2c; 1.
DR SUPFAM; SSF48619; SSF48619; 1.
PE 1: Evidence at protein level;
KW Calcium; Direct protein sequencing; Disulfide bond; Hydrolase;
KW Lipid degradation; Lipid metabolism; Metal-binding; Neurotoxin; Secreted;
KW Toxin.
FT CHAIN 1..>107
FT /note="Basic phospholipase A2 sphenotoxin subunit B"
FT /id="PRO_0000446056"
FT ACT_SITE 47
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU10035"
FT ACT_SITE 89
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT BINDING 27
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT BINDING 29
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT BINDING 31
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT BINDING 48
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT DISULFID 28..44
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT DISULFID 43..91
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT DISULFID 50..88
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT DISULFID 57..81
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT DISULFID 75..86
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT NON_CONS 90..91
FT /evidence="ECO:0000303|PubMed:30205237"
FT NON_TER 107
FT /evidence="ECO:0000303|PubMed:30205237"
SQ SEQUENCE 107 AA; 12556 MW; 34050799C1BF1D77 CRC64;
HLLQFNKMIK EETGKNAIPF YAFYGCYCGW GGSGKPKDAT DRCCFEHDCC YGKLTNCNTK
WDIYSYSLKD GYITCGKGTW CEKEVCECDK CLRRNLRTYK YGYMFYL
