Investigation of phospholipase-lipid interactions by optical detection of triplet state magnetic resonance spectroscopy.
We have investigated the binding of porcine pancreatic phospholipase A2 (PA2) to n-hexadecylphosphocholine (C16PN) micelles using optical detection of triplet state magnetic resonance (ODMR) spectroscopy. The zero field splittings (zfs) of the single Trp3 residue undergo significant changes upon binding of PA2 to C16PN micelles. Zfs titrations of PA2 vs C16PN indicate that the binding stoichiometry is C16PN:PA2 approximately 25. A reduction of the (E) parameter from 1.227 to 1.135 GHz is postulated to result from Stark effects caused by the binding of a polar group (possibly phosphocholine) near Trp3 in the PA2-C16PN micelle complex.
D000818:Animals; D002794:Choline / Q000031:analogs & derivatives*; D004792:Enzyme Precursors / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D010740:Phospholipases / Q000378:metabolism*; D010741:Phospholipases A / Q000378:metabolism*; D054467:Phospholipases A2; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000378:metabolism; D013552:Swine
D004792:Enzyme Precursors; D008823:Micelles; D010767:Phosphorylcholine; C039128:miltefosine; D010740:Phospholipases; D010741:Phospholipases A; D054467:Phospholipases A2; D002794:Choline