PLA2_like: Phospholipase A2, a super-family of secretory and cytosolic enzymes; the latter are either Ca dependent or Ca independent. PLA2 cleaves the sn-2 position of the glycerol backbone of phospholipids (PC or phosphatidylethanolamine), usually in a metal-dependent reaction, to generate lysophospholipid (LysoPL) and a free fatty acid (FA). The resulting products are either dietary or used in synthetic pathways for leukotrienes and prostaglandins. Often, arachidonic acid is released as a free fatty acid and acts as second messenger in signaling networks. Secreted PLA2s have also been found to specifically bind to a variety of soluble and membrane proteins in mammals, including receptors. As a toxin, PLA2 is a potent presynaptic neurotoxin which blocks nerve terminals by binding to the nerve membrane and hydrolyzing stable membrane lipids. The products of the hydrolysis (LysoPL and FA) cannot form bilayers leading to a change in membrane conformation and ultimately to a block in the release of neurotransmitters. PLA2 may form dimers or oligomers.
Structure:1POE; human secretory phospholipase A2 bound with transition-state analog (1-o-octyl-2-heptylphosphonyl-sn-glycero-3-phosphoethanolamine), contacts at 3.5 A.