Exploring the Conformational Odorant Space in the Olfactory Receptor Binding Region
摘要
We have ideated a novel mechanism of how odorants with differing and electronic-structural features can excite the same olfactory receptor. We explored the conformational space of an odorant and identified its likely “activating” or “inhibiting” conformers. The eventual challenge is to provide a molecular glimpse into how a few hundred olfactory receptors can discern several thousand odorants and odors—of various structures and functional groups. For a functionally characterized mouse olfactory receptor, mOR-EG, we tested odorant molecules with experimentally determined activating strengths: strong and weak. Vanillin—an odorant that strongly activates mOR-EG was used as a reference. The conformational space of each test odorant was explored and superimposed over the structure of the reference odorant. By narrowing our studies to mOR-EG’s strong activator, eugenol and weak activator, allyl benzene, we identified specific molecular features among conformations that were reproduced even for disparate-looking odorants. It is likely then that a specific conformation catalyzes OR activation leading to the perception of an odor. We explore activating conformers as opposed to an odorant’s gross chemical features such as aromatic rings, aliphatic chains, degree of bond-saturation, etc. Our studies can be extended to drug-design, primarily because olfactory receptors have a putative structure that is typical of type-A G- Protein Coupled Receptor. To accomplish the tasks represented in this work the BioSolveIT suite of software was used.