Biochemistry and evolution of OBP and CSP proteins

Publisher Summary This chapter describes the biochemical and evolutionary aspects of the peripheral sensory proteins of insects. The chapter particularly focuses on the subclassification of binding proteins, the diversity of gene structures, and the phyletic and molecular relatedness between binding proteins from different insect species. A high number of binding proteins related to odorant-binding proteins (OBPs) are present in various nonsensory organs, such as the hemolymph, brain, accessory, and salivary glands (TH12 proteins, sericotropin, B proteins, and D7 gene products). OBPs act as general transporters of hydrophobic molecules and develop to bind and solubilize odorant molecules. The chemosensory proteins (CSPs), which are expressed all over the body, conserve a functional polyvalence, while the specific expression of OBPs in the antennae support an adaptation of these proteins to the reception of hydrophobic odorants. The chapter also discusses the genetic studies that may lead to the elucidation of how specific transporter molecules have developed to a fine-tuned function in olfaction.