Picodiscs for facile protein-glycolipid interaction analysis.

Protein interactions with glycolipids are implicated in diverse cellular processes. However, the study of protein glycolipid complexes remains a significant experimental challenge. Here, we describe a powerful new assay that combines electrospray ionization mass spectrometry (ESI-MS) and picodiscs, which are composed of human sphingolipid activator protein Saposin A and a small number of phospholipids, to display glycolipids 1 1 a lipid environment for protein-glycolipid interaction studies in aqueous solution. Time-resolved measurements of enzyme catalyzed hydrolysis of glycolipid substrates and the detection of low, moderate, and high affinity protein glycolipid interactions serve to demonstrate the reliability and versatility of the assay.