An interdisciplinary team headed by Reinhold Tacke (Inorganic Chemistry, University of Würzburg), Philip Kraft (Scent Research, Givaudan Schweiz Inc.), and Hanns Hatt (Cell Biology, University of Bochum) have attempted a "scent prediction" to test their computer model of lily-of-the-valley fragrance receptor hOR17-4. This molecule was characterized in detail as the first human scent receptor by Hatt and his co-workers, who also discovered it in sperm.
A fragrance is usually composed of a mixture of many different scented substances. Each of these individual substances can react with several of the approximately 347 scent receptors in our nose and show a complex scent. "When developing new fragrances, we have to rely on correlations between structure and effect derived from model substances as well as intuition," says Kraft. With the help of sperm, however, it is possible to study the lily-of-the-valley receptor in virtual isolation and simulate the primary process of scent sensing by computer.
An olfactory receptor responds to a scent molecule when it fits into the receptor's binding cavity. If the structure of the cavity is known, it should be possible to use computer models to predict whether a scent activates the receptor in question and to what degree. To prove this theory, the scientists investigated how the replacement of one carbon atom with a silicon atom affects the scent of lily-of-the-valley fragrance components lilial and bourgeonal, and whether this subtle alteration, which has minimal influence on the molecular shape, can also be predicted quantitatively. The human nose was indeed fooled. Tacke says, "All four of the synthesized compounds had the typical floral aldehydic lily-of-the-valley fragrance, but didn't smell completely identical." However, near their threshold levels, it was no longer possible to tell these scents apart. "Only the most sensitive lily-of-the-valley receptor is activated at these concentrations," explains Hatt.
On the basis of calculated binding energies, the team had made a prediction of the scent intensities as well as the sensitivity of sperm to the test molecules. These predictions corresponded very closely to the experimentally observed results. As expected, the odor thresholds were significantly higher for the silicon analogues than for lilial and bourgeonal.
Original publication: Reinhold Tacke et al.; "Prediction of Perception: Probing the hOR17-4 Olfactory Receptor Model with Silicon Analogues of Bourgeonal and Lilial"; Angewandte Chemie International Edition 2007, 46, No. 18, 3367-3371.
A new experiment has made it possible to observe the effects of an electron in solution on the surrounding liquid. So-called hydrated electrons play a major role in many physical, chemical and biological processes. They are not bound to an atom or molecule and are free in the solution. Sinc ... more
Tens of thousands of feasible catalysts on the diameter of a hair
When searching for catalysts for the energy transition, materials consisting of at least five elements are considered highly promising. But there are theoretically millions of them – how do we identify the most powerful one? A Bochum-based research team led by Professor Alfred Ludwig, head ... more
Protecting biocatalysts from oxygen
Certain enzymes from bacteria and algae can produce molecular hydrogen from protons and electrons – an energy carrier on which many hopes are riding. All they need for this purpose is light energy. The major obstacle to their use is that they are destroyed by contact with oxygen. An interdi ... more
Making Drinking Water Bacteria-Free
Water contaminated with bacteria is a large threat to global health. A Chinese research team has described a simple new method of disinfection in the journal Angewandte Chemie. It is based on tiny biocompatible assemblies of atoms, known as quantum dots, made of silver sulfide with caps mad ... more
Huge amounts of technical or Kraft lignin are formed during pulp production. This lignin is difficult to process and so is usually just incinerated for heat production. A team of researchers, reporting in the journal Angewandte Chemie, have now succeeded in developing a green method for rec ... more
Until now, it has been clear: you can have a metal or a plastic, but not both in one. However, things don’t have to stay that way. In the journal Angewandte Chemie, a Chinese research team has now reported a polymer with a metallic backbone that is conductive, thermally stable, and has inte ... more
First steps towards a more climate-friendly streaming
In recent years, video streaming has increased significantly. While every German spent an average of 42 minutes a day watching online videos on YouTube, Netflix, Facebook or other platforms in 2019, a year later it was already 55 minutes - in the group of 14- to 29-year-olds even 130 minute ... more
Metamaterial for the terahertz age
An international research team, comprising scientists from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the Catalan Institute of Nanoscience and Nanotechnology and JMU Würzburg, has found a way of generating terahertz radiation by frequency conversion much more efficient than with previ ... more
Artificial Enzyme Splits Water
Chemists from Würzburg present a new enzyme-like molecular catalyst for water oxidation. Mankind is facing a central challenge: it must manage the transition to a sustainable and carbon dioxide-neutral energy economy. Hydrogen is considered a promising alternative to fossil fuels. It can be ... more
World's first toxicology testing strategy without animal testing adopted by OECD
The world’s first toxicology testing strategy without animal testing has been approved by the OECD (Organisation for Economic Co-operation and Development). The testing strategy consists of three so-called alternative methods. They can be used to predict whether a substance causes allergic ... more
IIVS Collaborates with BASF and Givaudan to Validate a Non-animal Test for Regulatory Submissions
The Institute for In Vitro Sciences (IIVS), with an established track record in the validation of alternatives to animal testing, is teaming up with BASF and Givaudan to validate an improved skin sensitization reactivity method to address the needs of toxicologists and regulators. Scientist ... more
A Fragrance That Breaks the Rules
Approximately one third of all fragrances on the market contain vetiver oil as a key ingredient, for which no synthetic odorant is commercially available. Instead it has to be distilled from the dried roots of vetiver grass. To find out about the structural requirements of vetiver odorants, ... more
Givaudan is the leading company in the flavours and fragrance industry with a vision to be the Essential Source of Sensory Innovation for customers, driven by a mutual passion for excellence. Through unique sensory expertise and consumer insight, Givaudan provides customers with the taste ... more
Givaudan is the leading company in the flavours and fragrance industry with a vision to be the Essential Source of Sensory Innovation for customers, driven by a mutual passion for excellence. Through unique sensory expertise and consumer insight, Givaudan provides customers with the taste ... more
Givaudan is the leading company in the flavours and fragrance industry with a vision to be the Essential Source of Sensory Innovation for customers, driven by a mutual passion for excellence. Through unique sensory expertise and consumer insight, Givaudan provides customers with the taste ... more
