P22640 · PA2H_PROMU

Function

function

Snake venom phospholipase A2 (PLA2) that has almost no phospholipase A2 activity. Is myotoxic (By similarity).
Displays edema-inducing activities (PubMed:2029535).
A model of myotoxic mechanism has been proposed: an apo Lys49-PLA2 is activated by the entrance of a hydrophobic molecule (e.g. fatty acid) at the hydrophobic channel of the protein leading to a reorientation of a monomer (By similarity).
This reorientation causes a transition between 'inactive' to 'active' states, causing alignment of C-terminal and membrane-docking sites (MDoS) side-by-side and putting the membrane-disruption sites (MDiS) in the same plane, exposed to solvent and in a symmetric position for both monomers (By similarity).
The MDoS region stabilizes the toxin on membrane by the interaction of charged residues with phospholipid head groups (By similarity).
Subsequently, the MDiS region destabilizes the membrane with penetration of hydrophobic residues (By similarity).
This insertion causes a disorganization of the membrane, allowing an uncontrolled influx of ions (i.e. calcium and sodium), and eventually triggering irreversible intracellular alterations and cell death (By similarity).

Caution

Does not bind calcium as one of the calcium-binding sites is lost (Asp->Lys in position 48, which corresponds to 'Lys-49' in the current nomenclature).

Features

Showing features for site.

TypeIDPosition(s)Description
Site106Important residue of the cationic membrane-docking site (MDoS)
Site109Important residue of the cationic membrane-docking site (MDoS)
Site112Cationic membrane-docking site (MDoS)
Site113Cationic membrane-docking site (MDoS)
Site115Hydrophobic membrane-disruption site (MDiS)

GO annotations

AspectTerm
Cellular Componentextracellular region
Molecular Functioncalcium ion binding
Molecular Functioncalcium-dependent phospholipase A2 activity
Molecular Functionphospholipid binding
Molecular Functiontoxin activity
Biological Processarachidonic acid secretion
Biological Processlipid catabolic process
Biological Processnegative regulation of T cell proliferation
Biological Processphospholipid metabolic process

Keywords

Names & Taxonomy

Protein names

  • Recommended name
    Basic phospholipase A2 homolog
  • Short names
    svPLA2 homolog
  • Alternative names
    • TMV-K49

Organism names

Accessions

  • Primary accession
    P22640

Subcellular Location

Keywords

PTM/Processing

Features

Showing features for chain, disulfide bond.

TypeIDPosition(s)Description
ChainPRO_00001617061-122Basic phospholipase A2 homolog
Disulfide bond26↔116
Disulfide bond28↔44
Disulfide bond43↔96
Disulfide bond49↔122
Disulfide bond50↔89
Disulfide bond57↔82
Disulfide bond75↔87

Keywords

Expression

Tissue specificity

Expressed by the venom gland.

Interaction

Subunit

Homodimer; non-covalently linked.

Structure

Family & Domains

Features

Showing features for region.

TypeIDPosition(s)Description
Region106-117Important for membrane-damaging activities in eukaryotes and bacteria; heparin-binding

Sequence similarities

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    122
  • Mass (Da)
    13,809
  • Last updated
    1991-08-01 v1
  • Checksum
    96F567227B825E8B
SLIELGKMIFQETGKNPVKNYGLYLCNCGVGNRGKPVDATDRCCFVHKCCYKKVTGCDPKKDRYSYSWENKAIVCGEKNPPCLKQVCECDKAVAICLRENLQTYDKKHRVTVKFLCKAPESC

Keywords

Sequence databases

Similar Proteins

Disclaimer

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