CHAMPAIGN, Ill. A new study of the sense of smell lends support to a controversial theory of olfaction: Our noses can distinguish both the shape and the vibrational characteristics of odorant molecules.
The study, in the journal Physical Chemistry Chemical Physics, demonstrates the feasibility of the theory first proposed decades ago that the vibration of an odorant molecule's chemical bonds the wagging, stretching and rocking of the links between atoms contributes to our ability to distinguish one smelly thing from another.
"The theory goes that when the right odorant binds to its receptor, the odorant's molecular vibration allows electrons to transfer from one part of the receptor to another," said University of Illinois physics and Beckman Institute professor Klaus Schulten, who conducted the analysis with postdoctoral researcher Ilia Solov'yov and graduate student Po-Yao Chang. "This electron transfer appears to fine-tune the signal the receptor receives."
Many who study olfaction maintain that odorant receptors recognize only an odorant's shape and surface characteristics. They dismiss the idea that molecular vibration has anything to do with it, Schulten said. Likewise, some proponents of the vibrational theory think that molecular vibration only, and not shape, guides the sense of smell. Schulten and his colleagues belong to a "third camp" that sees evidence for both, he said.
The vibrational theory of olfaction is supported by studies showing that insects, humans and other animals can tell the differenc
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University of Illinois at Urbana-Champaign