iOBPdb – A Database for Experimentally Determined Functional Characterization of Odorant Binding Proteins

Abstract

Summary/AbstractOdorant binding proteins, OBPs, are a diverse family of small, globular, extra-cellular proteins solubilize volatile organic compounds (VOCs) so they can be internalized and transported by an organism. Since their initial discovery in the early eighties 1, thousands of OBPs have been identified through genome sequencing and characterized by fluorescence ligand binding assays 2. While individual OBPs have been studied in the context of their roles in specific organism, there have been no studies towards the understanding of the comparative structure-function relations of all known OBPs, primarily due to a lack of a centralized database that incorporates the binding affinity with the structure of all OBPs. Incorporating OBP information into a database requires not only an extensive search of all existing resources, but also creating a useful platform that relates sequence structures to target functions. Combining 215 functional studies containing 381 unique OBPs from 91 insect species we created a database, iOBPdb: https://iobpdb.herokuapp.com, of OBP binding affinities for a wide range of VOC targets. We demonstrate here that the construction of this initial database provides powerful search and associative capabilities including interrogating odor binding proteins as clusters and groups by sequence similarity versus protein and target molecular weights, and by the functional groups of the VOC targets. The comparative interrogation of the probe-target recognition allows for a more comprehensive understanding of the underlying structural features of all OBPs that had not been possible by only examining the OBPs individually. We present our results in a variety of phylogenetic representations as well as providing the binding profiles of OBP groups to VOC functional moieties. Potential applications include development of molecular probes for biosensors, novel bioassays and drugs, discovery of novel pesticides which inhibit VOC / OBP interactions, as well providing a foundational basis for the functional understanding of odor sensing and perception in the brain.Abstract Figure