PA2BB_SISTE
ID PA2BB_SISTE Reviewed; 138 AA.
AC Q6EER2;
DT 05-SEP-2012, integrated into UniProtKB/Swiss-Prot.
DT 16-AUG-2004, sequence version 1.
DT 03-AUG-2022, entry version 70.
DE RecName: Full=Basic phospholipase A2 sistruxin B;
DE Short=svPLA2;
DE EC=3.1.1.4;
DE AltName: Full=Phosphatidylcholine 2-acylhydrolase;
DE Flags: Precursor;
OS Sistrurus tergeminus (Western massasauga) (Sistrurus catenatus tergeminus).
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC Serpentes; Colubroidea; Viperidae; Crotalinae; Sistrurus.
OX NCBI_TaxID=8757;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 17-39, FUNCTION,
RP BIOPHYSICOCHEMICAL PROPERTIES, SUBUNIT, AND MASS SPECTROMETRY.
RC TISSUE=Venom, and Venom gland;
RX PubMed=15032748; DOI=10.1042/bj20040125;
RA Chen Y.-H., Wang Y.-M., Hseu M.-J., Tsai I.-H.;
RT "Molecular evolution and structure-function relationships of crotoxin-like
RT and asparagine-6-containing phospholipases A2 in pit viper venoms.";
RL Biochem. J. 381:25-34(2004).
CC -!- FUNCTION: Snake venom phospholipase A2 (PLA2) that shows presynaptic
CC neurotoxicity. PLA2 catalyzes the calcium-dependent hydrolysis of the
CC 2-acyl groups in 3-sn-phosphoglycerides. {ECO:0000269|PubMed:15032748}.
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, ECO:0000255|PROSITE-
CC ProRule:PRU10036};
CC -!- COFACTOR:
CC Name=Ca(2+); Xref=ChEBI:CHEBI:29108; Evidence={ECO:0000250};
CC Note=Binds 1 Ca(2+) ion. {ECO:0000250};
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC Vmax=385 umol/min/mg enzyme with DPPC + deoxycholate as substrate (at
CC pH 7.4 and 37 degrees Celsius) {ECO:0000269|PubMed:15032748};
CC Vmax=192 umol/min/mg enzyme with DPPC + Triton X-100 as substrate (at
CC pH 7.4 and 37 degrees Celsius) {ECO:0000269|PubMed:15032748};
CC Note=When tested as a monomer.;
CC -!- SUBUNIT: Heterodimer of an acidic subunit and a basic chain. The acidic
CC subunit is non-toxic, without enzymatic activity and comprises 3
CC peptides that are cross-linked by 7 disulfide bridges. The basic
CC subunit is toxic, has phospholipase A2 activity and is composed of a
CC single chain. {ECO:0000269|PubMed:15032748}.
CC -!- SUBCELLULAR LOCATION: Secreted.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC -!- MASS SPECTROMETRY: Mass=14122; Method=Electrospray;
CC Evidence={ECO:0000269|PubMed:15032748};
CC -!- SIMILARITY: Belongs to the phospholipase A2 family. Group II subfamily.
CC D49 sub-subfamily. {ECO:0000305}.
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DR EMBL; AY355170; AAR14164.1; -; mRNA.
DR AlphaFoldDB; Q6EER2; -.
DR SMR; Q6EER2; -.
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; IPR033112; PLipase_A2_Asp_AS.
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.
DR PROSITE; PS00119; PA2_ASP; 1.
DR PROSITE; PS00118; PA2_HIS; 1.
PE 1: Evidence at protein level;
KW Calcium; Direct protein sequencing; Disulfide bond; Hydrolase;
KW Lipid degradation; Lipid metabolism; Metal-binding; Neurotoxin;
KW Presynaptic neurotoxin; Secreted; Signal; Toxin.
FT SIGNAL 1..16
FT /evidence="ECO:0000269|PubMed:15032748"
FT CHAIN 17..138
FT /note="Basic phospholipase A2 sistruxin B"
FT /id="PRO_0000418572"
FT ACT_SITE 63
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT ACT_SITE 105
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT BINDING 43
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT BINDING 45
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT BINDING 47
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT BINDING 64
FT /ligand="Ca(2+)"
FT /ligand_id="ChEBI:CHEBI:29108"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT DISULFID 42..131
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT DISULFID 44..60
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT DISULFID 59..111
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT DISULFID 65..138
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT DISULFID 66..104
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT DISULFID 73..97
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT DISULFID 91..102
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT CONFLICT 31
FT /note="K -> A (in Ref. 1; AA sequence)"
FT /evidence="ECO:0000305"
SQ SEQUENCE 138 AA; 15844 MW; 2F482EB371CBFED4 CRC64;
MRALWIVAVL LVGVEGNLLQ FNKMIKFETN KNAIPFYAFY GCYCGWGGRG RPKDATDRCC
FVHDCCYGKL PNCDTKWDIY SYSLKSGFIT CGKGTWCEEQ ICECDRVAAE CLRRSLSTYK
YGYMFYLDSR CKGPSEQC
