Shakespeare's suggestion that calling a rose by any other name would not change its sweet smell may not be true anymore, for scientists say that the flower's fragrance can be modified by altering the shape of the molecules that generate it.
Dr. Kevin Ryan, Assistant Professor of Chemistry at The City College of New York (CCNY) and collaborators in the laboratory of Dr. Stuart Firestein, Professor of Biology at Columbia University, say that their findings have potential applications in the design of flavours and fragrances.
The researchers highlighted the fact that when odour-producing molecules, known as odorants, pass through the nose, they trigger intracellular changes in a subset of the approximately 400 different varieties olfactory sensory neurons (OSN) housed in the nose's internal membrane tissue.
According to them, the unique reaction pattern produced, known as the olfactory code, is sent as a signal to the brain, which leads to perception of odours.
With a view to determining how these receptor cells respond when odorants change their shape, the researchers studied the odorant octanal, an eight-carbon aldehyde, that occurs in many flowers and citrus fruits.
Professor Ryan revealed that octanal is a structurally flexible molecule that can adapt to many different shapes by rotating its chemical bonds.
He and his colleagues designed and synthesized eight-carbon aldehydes that resembled octanal, but had their carbon chains locked by adding one additional bond.
The researchers tested these molecules on genetically engineered OSNs, known to respond to octanal, in Professor Firestein's laboratory at Columbia.
They observed that the aldehyde molecules that could stretch to their greatest length triggered strong activity in the OSNs, but those whose carbon chains were constrained into a U shape blocked the receptor and left the cell unable to sense octanal.
"Conformationally constrained odorants were more selective in the number of OSNs they activated. The results indicate that these odorant molecules might be able to alter fragrance mixture odors in two ways: by muting the activity of flexible odorants present in a mixture and by activating a smaller subset of OSNs than chemically related flexible odorants. This would produce a different olfactory code signature," Professor Ryan said.
Given that olfactory receptors belong to the G-protein coupled receptor (GPCR) class of proteins-a family of molecules found in cell membranes throughout the body that are used by many commercial pharmaceuticals-Professor Ryan believes that his team's findings could also have applications to GPCR drug design also.
A research article on the study has been published by the journal Chemistry and Biology.