PA2BD_CRODU
ID PA2BD_CRODU Reviewed; 122 AA.
AC C0HM14;
DT 25-MAY-2022, integrated into UniProtKB/Swiss-Prot.
DT 25-MAY-2022, sequence version 1.
DT 03-AUG-2022, entry version 2.
DE RecName: Full=Phospholipase A2 crotoxin basic subunit CBd {ECO:0000303|PubMed:8513799};
DE Short=CTX subunit CBd {ECO:0000303|PubMed:8513799};
DE Short=svPLA2 {ECO:0000305};
DE EC=3.1.1.4 {ECO:0000255|PROSITE-ProRule:PRU10035, ECO:0000255|PROSITE-ProRule:PRU10036, ECO:0000269|PubMed:8513799};
DE AltName: Full=Phosphatidylcholine 2-acylhydrolase {ECO:0000305};
DE Flags: Fragment;
OS Crotalus durissus terrificus (South American rattlesnake).
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC Serpentes; Colubroidea; Viperidae; Crotalinae; Crotalus.
OX NCBI_TaxID=8732;
RN [1] {ECO:0000305}
RP PROTEIN SEQUENCE, SUBCELLULAR LOCATION, AND TISSUE SPECIFICITY.
RX PubMed=3753003; DOI=10.1016/0003-9861(86)90005-6;
RA Aird S.D., Kaiser I.I., Lewis R.V., Kruggel W.G.;
RT "A complete amino acid sequence for the basic subunit of crotoxin.";
RL Arch. Biochem. Biophys. 249:296-300(1986).
RN [2] {ECO:0000305}
RP FUNCTION, CATALYTIC ACTIVITY, BIOPHYSICOCHEMICAL PROPERTIES, SUBUNIT, AND
RP TOXIC DOSE.
RX PubMed=8513799; DOI=10.1111/j.1432-1033.1993.tb17946.x;
RA Faure G., Harvey A.L., Thomson E., Saliou B., Radvanyi F., Bon C.;
RT "Comparison of crotoxin isoforms reveals that stability of the complex
RT plays a major role in its pharmacological action.";
RL Eur. J. Biochem. 214:491-496(1993).
RN [3] {ECO:0000305}
RP MASS SPECTROMETRY, AND SUBCELLULAR LOCATION.
RC TISSUE=Venom;
RX PubMed=8033889; DOI=10.1111/j.1432-1033.1994.tb18978.x;
RA Faure G., Choumet V., Bouchier C., Camoin L., Guillaume J.-L., Monegier B.,
RA Vuilhorgne M., Bon C.;
RT "The origin of the diversity of crotoxin isoforms in the venom of Crotalus
RT durissus terrificus.";
RL Eur. J. Biochem. 223:161-164(1994).
RN [4] {ECO:0000305}
RP INTERACTION WITH CICS, AND INHIBITION OF CROTOXIN BY CICS.
RX PubMed=10903514; DOI=10.1046/j.1432-1327.2000.01532.x;
RA Faure G., Villela C., Perales J., Bon C.;
RT "Interaction of the neurotoxic and nontoxic secretory phospholipases A2
RT with the crotoxin inhibitor from Crotalus serum.";
RL Eur. J. Biochem. 267:4799-4808(2000).
RN [5] {ECO:0000305}
RP FUNCTION.
RX PubMed=12657321; DOI=10.1016/s0041-0101(02)00394-x;
RA Faure G., Copic A., Le Porrier S., Gubensek F., Bon C., Krizaj I.;
RT "Crotoxin acceptor protein isolated from Torpedo electric organ: binding
RT properties to crotoxin by surface plasmon resonance.";
RL Toxicon 41:509-517(2003).
RN [6] {ECO:0007744|PDB:6TMY}
RP X-RAY CRYSTALLOGRAPHY (1.8 ANGSTROMS).
RX PubMed=33202772; DOI=10.3390/molecules25225290;
RA Nemecz D., Ostrowski M., Ravatin M., Saul F., Faure G.;
RT "Crystal Structure of Isoform CBd of the Basic Phospholipase A2 Subunit of
RT Crotoxin: Description of the Structural Framework of CB for Interaction
RT with Protein Targets.";
RL Molecules 25:0-0(2020).
CC -!- FUNCTION: Heterodimer CA-CB: Crotoxin is a potent presynaptic
CC neurotoxin that possesses phospholipase A2 (PLA2) activity and exerts a
CC lethal action by blocking neuromuscular transmission (PubMed:8513799).
CC It consists of a non-covalent association of a basic and weakly toxic
CC PLA2 subunit (CBa2, CBb, CBc, or CBd), with a small acidic, non-
CC enzymatic and non-toxic subunit (CA1, CA2, CA3 or CA4)
CC (PubMed:8513799). The complex acts by binding to a specific 48-kDa
CC protein (R48) receptor located on presynaptic membranes, forming a
CC transient ternary complex CA-CB-R48, followed by dissociation of the
CC CA-CB complex and release of the CA subunit (PubMed:12657321). At
CC equilibrium, only the CB subunits remain associated with the specific
CC crotoxin receptor (PubMed:12657321). In addition to neurotoxicity,
CC crotoxin has been found to exert myotoxicity, nephrotoxicity, and
CC cardiovascular toxicity (By similarity). Moreover, anti-inflammatory,
CC immunomodulatory, anti-tumor and analgesic effects of crotoxin have
CC also been reported (By similarity). {ECO:0000250|UniProtKB:P62022,
CC ECO:0000269|PubMed:12657321, ECO:0000269|PubMed:8513799}.
CC -!- FUNCTION: Monomer CBd: The basic subunit of crotoxin is a snake venom
CC phospholipase A2 (PLA2) that exhibits weak neurotoxicity (10-fold less
CC than the heterodimer) and very strong anticoagulant effects by binding
CC to factor Xa (F10) and inhibiting the prothrombinase activity (By
CC similarity). In addition, it shows the same effects described for the
CC heterodimer and binds the nucleotide-binding domain (NBD1) of CFTR
CC chloride channels and increases the channel current (By similarity).
CC PLA2 catalyzes the calcium-dependent hydrolysis of the 2-acyl groups in
CC 3-sn-phosphoglycerides (PubMed:8513799). {ECO:0000250|UniProtKB:P62022,
CC ECO:0000269|PubMed:8513799}.
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, ECO:0000269|PubMed:8513799};
CC -!- COFACTOR:
CC Name=Ca(2+); Xref=ChEBI:CHEBI:29108;
CC Evidence={ECO:0000250|UniProtKB:P62022};
CC Note=Binds 1 Ca(2+) ion. {ECO:0000250|UniProtKB:P62022};
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC KM=0.06 uM for 1-palmitoyl-2-(10-pyrenyldecanoyl)-sn-glycero-3-
CC monomethyl phosphatidic acid (monomer CBd)
CC {ECO:0000269|PubMed:8513799};
CC KM=0.35 uM for 1-palmitoyl-2-(10-pyrenyldecanoyl)-sn-glycero-3-
CC monomethyl phosphatidic acid (class 1 heterodimer CA2-CBd)
CC {ECO:0000269|PubMed:8513799};
CC KM=0.3 uM for 1-palmitoyl-2-(10-pyrenyldecanoyl)-sn-glycero-3-
CC monomethyl phosphatidic acid (class 1 heterodimer CA3-CBd)
CC {ECO:0000269|PubMed:8513799};
CC Vmax=19.7 umol/min/mg enzyme (monomer CBd)
CC {ECO:0000269|PubMed:8513799};
CC Vmax=4.6 umol/min/mg enzyme (class 1 heterodimer CA2-CBd)
CC {ECO:0000269|PubMed:8513799};
CC Vmax=4 umol/min/mg enzyme (class 1 heterodimer CA3-CBd)
CC {ECO:0000269|PubMed:8513799};
CC -!- SUBUNIT: Heterodimer of one of the acidic (CA1, CA2, CA3 or CA4) and
CC one of the basic (CBa1, CBa2, CBb, CBc or CBd) subunits; non-covalently
CC linked (PubMed:8513799). The acidic subunit is non-toxic, without
CC enzymatic activity and comprises 3 peptides that are cross-linked by 5
CC disulfide bridges (PubMed:8513799). The basic subunit is toxic, has
CC phospholipase A2 activity and is composed of a single chain
CC (PubMed:8513799). Multiple variants of each subunit give different
CC crotoxin complexes that can be subdivided into 2 classes: (1) those of
CC high toxicity, low PLA2 activity (CBb, CBc and CBd linked with high
CC affinity to any CA) and high stability (K(d)=4.5 nM) and (2) those of
CC moderate toxicity, high PLA2 activity (CBa2 linked with low affinity to
CC any CA) and low stability (K(d)=25 nM) (PubMed:8513799). Interacts with
CC crotoxin inhibitor from Crotalus serum (CICS); the interaction leads to
CC dissociation of the CA-CB heterodimer and to inhibition of PLA2
CC activity of the CB subunit (PubMed:10903514). Interacts with human NBD1
CC domain of CFTR (By similarity). {ECO:0000250|UniProtKB:P62022,
CC ECO:0000269|PubMed:10903514, ECO:0000269|PubMed:8513799}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:3753003,
CC ECO:0000269|PubMed:8033889}.
CC -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC {ECO:0000305|PubMed:3753003}.
CC -!- MASS SPECTROMETRY: Mass=14234; Mass_error=1; Method=Electrospray;
CC Evidence={ECO:0000269|PubMed:8033889};
CC -!- TOXIC DOSE: In monomer CBd, LD(50) is 480 ug/kg by intravenous
CC injection into mice. {ECO:0000269|PubMed:8513799}.
CC -!- TOXIC DOSE: In class 1 heterodimer CA2-CBd, LD(50) is 70 ug/kg by
CC intravenous injection into mice. {ECO:0000269|PubMed:10903514}.
CC -!- TOXIC DOSE: In class 1 heterodimer CA3-CBd, LD(50) is 90 ug/kg by
CC intravenous injection into mice. {ECO:0000269|PubMed:10903514}.
CC -!- MISCELLANEOUS: The crotoxin heterodimer is inhibited by the crotoxin
CC inhibitor from Crotalus serum (CICS) (PubMed:10903514). CICS
CC neutralizes the lethal potency of crotoxin and inhibits its PLA2
CC activity (PubMed:10903514). CICS only binds tightly to the CB subunit
CC and induces the dissociation of the heterodimer (PubMed:10903514).
CC Tested on the CA2-CBd heterodimer (PubMed:10903514).
CC {ECO:0000269|PubMed:10903514}.
CC -!- SIMILARITY: Belongs to the phospholipase A2 family. Group II subfamily.
CC D49 sub-subfamily. {ECO:0000305}.
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DR PDB; 6TMY; X-ray; 1.80 A; A/B/C/D/E/F=1-122.
DR PDBsum; 6TMY; -.
DR GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR GO; GO:0016787; F:hydrolase activity; IEA:UniProtKB-KW.
DR GO; GO:0099106; F:ion channel regulator activity; IEA:UniProtKB-KW.
DR GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR GO; GO:0016042; P:lipid catabolic process; IEA:UniProtKB-KW.
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.
PE 1: Evidence at protein level;
KW 3D-structure; Blood coagulation cascade inhibiting toxin; Calcium;
KW Direct protein sequencing; Disulfide bond; Hemostasis impairing toxin;
KW Hydrolase; Ion channel impairing toxin; Lipid degradation;
KW Lipid metabolism; Metal-binding; Neurotoxin; Presynaptic neurotoxin;
KW Secreted; Toxin.
FT CHAIN <1..122
FT /note="Phospholipase A2 crotoxin basic subunit CBd"
FT /id="PRO_0000455423"
FT ACT_SITE 47
FT /evidence="ECO:0000250|UniProtKB:P62022"
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 SITE 1
FT /note="Responsible for the weak stability and toxicity"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT SITE 2
FT /note="Putative interfacial binding surface (IBS)"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT SITE 3
FT /note="Putative interfacial binding surface (IBS)"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT SITE 7
FT /note="Putative interfacial binding surface (IBS)"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT SITE 10
FT /note="Putative interfacial binding surface (IBS)"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT SITE 17
FT /note="Putative interfacial binding surface (IBS)"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT SITE 22
FT /note="Putative interfacial binding surface (IBS)"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT SITE 23
FT /note="Putative interfacial binding surface (IBS)"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT SITE 60
FT /note="Putative interfacial binding surface (IBS)"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT SITE 103
FT /note="Putative interfacial binding surface (IBS)"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT SITE 117
FT /note="Responsible for the higher anticoagulant activity
FT (compared with CBa2)"
FT /evidence="ECO:0000250|UniProtKB:P62022"
FT DISULFID 26..115
FT /evidence="ECO:0007744|PDB:6TMY"
FT DISULFID 28..44
FT /evidence="ECO:0007744|PDB:6TMY"
FT DISULFID 43..95
FT /evidence="ECO:0007744|PDB:6TMY"
FT DISULFID 49..122
FT /evidence="ECO:0007744|PDB:6TMY"
FT DISULFID 50..88
FT /evidence="ECO:0007744|PDB:6TMY"
FT DISULFID 57..81
FT /evidence="ECO:0007744|PDB:6TMY"
FT DISULFID 75..86
FT /evidence="ECO:0007744|PDB:6TMY"
FT NON_TER 1
FT /evidence="ECO:0000305"
SQ SEQUENCE 122 AA; 14258 MW; CC5EFD491B33C79A CRC64;
HLLQFNKMIK FETRKNAIPF YAFYGCYCGW GGRGRPKDAT DRCCFVHDCC YGKLAKCNTK
WDIYRYSLKS GYITCGKGTW CEEQICECDR VAAECLRRSL STYKYGYMFY PDSRCRGPSE
TC
