University of Illinois physicist Klaus Schulten and colleagues have added another 11 pages to the pile of theoretical physics papers claiming that the vibration theory of smell is theoretically possible. In an amusing twist, Schulten talks trash about the other vibration theory fan-boys:
Those who suggested that molecular vibration played a role in odorant recognition in previous studies “didn’t know about [Rudolph] Marcus’ theory and they didn’t do quantum chemical calculations,” Schulten said. “They argued very much on principle (that it was possible). So we are saying now, yes, it is really possible even when you do the most complete and reliable calculations.”Those idiots! They like so totally forgot the quantum chemical calculations.
Here at FirstNerve we don’t know a Huang-Rhys factor from a hybrid Becke-type three parameter exchange functional, but we sure as hell enjoy watching theoretical physicists get into a food fight.
For everyone else observing from the sidelines, here are three important take away points:
First, in advocating a “vibrationally assisted” mechanism of olfaction the authors concede that a molecule’s shape and size do matter. This is a big walkback from pure vibration theory.
Second, the authors conclude only that the new model is “energetically feasible,” not that it is biologically realistic.
Finally, since they acknowledge that “receptor structure presently is still unknown,” their conclusions are largely a matter of conjecture. Until there is some convincing biology, their 19 different equations are not worth the pixels they are printed in.
The study discussed here is “Vibrationally assisted electron transfer mechanism of olfaction: myth or reality?,” by Ilia A. Solov’yov, Po-Yao Chang, & Klaus Schulten, published online July 17, 2012 in Physical Chemistry Chemical Physics. It is available here.