Nav: Home

A fish of all flavors

June 08, 2017

Receptors are how the body senses its environment. Upon the binding of a ligand, a receptor will initiate a chain of events that elicits a response. Our olfactory system depends on approximately 400 receptors to give us our sense of smell. Taste, however, operates with a much smaller number: The combination of only three members of the taste receptor type 1 (T1r) family can detect a wide range of sweet and savory flavours in humans.

"T1r heterodimers can perceive most sweet and umami taste substances," says Prof. Junichi Takagi of Osaka University. "To understand this perception, we looked at the atomic structure of the heterodimer."

Our bodies sense a flavour when an amino acid of the food binds to a heterodimer of two T1r members. Takagi is an expert of structural biology who studies the physical conformations of receptors upon binding to their ligands.

"The lock-and-key theory explains most ligand-receptor bindings. T1r is unusual because this theory does not seem to apply. We thought it would make an interesting research study."

Takagi was approached by Prof. Atsuko Yamashita at Okayama University who had been studying the T1r2-T1r3 heterodimer of medaka fish for years. This heterodimer binds to a wide range of amino acids for the perception of savory flavours. To measure the structure at the atomic level, they used Takagi's expertise as well as the synchrotron radiation equipment at RIKEN SPring-8 in Japan.

The research team found the heterodimer structure was approximately the same regardless of the amino acid bound, but the affinity for the amino acid was ensured together with the shell-structured water molecules around the amino acid. This characteristic could explain how a single heterodimer can bind to an array of ligands.

"We found the space in which the ligand binds T1r2 is much bigger than the ligand itself. This larger space could account for the structured water," Yamashita said. "The space in lock-and-key receptors is much smaller."

A similar property is found in receptors that pass different types of drugs, suggesting this mechanism may be constant for non-specific receptors.

Although formation of the heterodimer is necessary for perception, the findings indicated that T1r2 was responsible for detecting different amino acids and that binding to T1r3 did not have a direct role in recognizing flavours.

For preparation reasons of the receptors, the group chose to study the medaka fish T1r2-T1r3 heterodimer over the human version. Yet, because the T1r family is universal in higher-levels animals, these findings should make an informative model for taste sensation in humans.
-end-


Osaka University

Related Amino Acids Articles:

A natural amino acid could be a novel treatment for polyglutamine diseases
Researchers from Osaka University, National Center of Neurology and Psychiatry, and Niigata University identified the amino acid arginine as a potential disease-modifying drug for polyglutamine diseases, including familial spinocerebellar ataxia and Huntington disease.
Alzheimer's: Can an amino acid help to restore memories?
Scientists at the Laboratoire des Maladies Neurodégénératives (CNRS/CEA/Université Paris-Saclay) and the Neurocentre Magendie (INSERM/Université de Bordeaux) have just shown that a metabolic pathway plays a determining role in Alzheimer's disease's memory problems.
New study indicates amino acid may be useful in treating ALS
A naturally occurring amino acid is gaining attention as a possible treatment for ALS following a new study published in the Journal of Neuropathology & Experimental Neurology.
Breaking up amino acids with radiation
A new experimental and theoretical study published in EPJ D has shown how the ions formed when electrons collide with one amino acid, glutamine, differ according to the energy of the colliding electrons.
To make amino acids, just add electricity
By finding the right combination of abundantly available starting materials and catalyst, Kyushu University researchers were able to synthesize amino acids with high efficiency through a reaction driven by electricity.
Nanopores can identify the amino acids in proteins, the first step to sequencing
While DNA sequencing is a useful tool for determining what's going on in a cell or a person's body, it only tells part of the story.
Differentiating amino acids
Researchers develop the foundation for direct sequencing of individual proteins.
Simulating amino acid starvation may improve dengue vaccines
In a new paper in Science Signaling, researchers at the University of Hyderabad in India and the Cornell University College of Veterinary Medicine show that a plant-based compound called halofuginone improves the immune response to a potential vaccine against dengue virus.
CoP-electrocatalytic reduction of nitroarenes: a controllable way to azoxy-, azo- and amino-aromatic
The development of a green, efficient and highly controllable manner to azoxy-, azo- and amino-aromatics from nitro-reduction is extremely desirable both from academic and industrial points of view.
Origin of life insight: peptides can form without amino acids
Peptides, one of the fundamental building blocks of life, can be formed from the primitive precursors of amino acids under conditions similar to those expected on the primordial Earth, finds a new UCL study published in Nature.
More Amino Acids News and Amino Acids Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.