Lipid interactions involved with pheromone binding protein function in Lymantria dispar

The mechanism for insect olfaction is not fully understood. Pheromone-binding proteins (PBPs) are hypothesized to be critical for proper chemical signaling in insects. Using a pheromone-binding assay I have shown that endogenous fatty acids, which bind Lymantria dispar PBP1 and PBP2, cause increased affinity for pheromone. Using circular dichroism spectroscopy, I have shown that the structures of PBP1 and PBP2 are altered by the binding of endogenous ligands. I propose that the altered conformation and increased affinity are related. The large concentration of fatty acids found in the sensillar lymph, where PBP1 and PBP2 have access to these ligands, is well above the critical micellar concentration. With various analytical techniques, most importantly of which was mass spectrometry, I identified many lipid components found in L. dispar’s lipidome. Analysis has provided insight into lipid bilayer preservation in the presence of endogenous fatty acid micelles. This thesis work provides evidence that lipids play an integral role in PBP function and proposes that they may be critical for olfaction.