In the advance online publication of Nature on Aug. 20, UT Medical School Assistant Professor C.S. Raman, Ph.D., and his colleagues report that they were able to manipulate flavor enzymes found in a popular plant model, Arabidopsis thaliana, by genetic means. The enzymes—allene oxide synthase (AOS) and hydroperoxide lyase (HPL)—produce jasmonate (responsible for the unique scent of jasmine flowers) and green leaf volatiles (GLV) respectively. GLVs confer characteristic aromas to fruits and vegetables.
Green leaf volatiles and jasmonates emitted by plants also serve to ward off predators. “Mind you plants can’t run away from bugs and other pests. They need to deal with them. One of the things they do is to release volatile substances into the air so as to attract predators of the bugs,” Raman said.
“Genetic engineering/modification (GM) of green leaf volatile production holds significant potential towards formulating environmentally friendly pest-control strategies. It also has important implications for manipulating food flavor,” said Raman, the senior author. “For example, the aroma of virgin olive oil stems from the volatiles synthesized by olives. By modifying the activity of enzymes that generate these substances, it may be possible to alter the flavor of the resulting oils.”
According to Raman, “Our work shows how you can convert one enzyme to another and, more importantly, provides the needed information for modifying the GLV production in plants.” The scientists made 3-D images of the enzymes, which allowed them to make a small, but specific, genetic change in AOS, leading to the generation of HPL.
AOS and HPL are part of a super family of enzymes called cytochrome P450. P450 family enzymes are found in most bacteria and all known plants and animals. Although AOS or HPL are not found in humans, there are related P450 family members that help metabolize nearly half of the pharmaceuticals currently in use. In plants, AOS and HPL break down naturally-occurring, organic peroxides into GLV and jasmonate molecules. “Each flavor has a different chemical profile,” Raman said.
“A notable strength of this manuscript is the combined use of structural and evolutionary biology to draw new insights regarding enzyme function. These insights led to the striking demonstration that a single amino acid substitution converts one enzyme into another, thereby showing how a single point mutation can contribute to the evolution of different biosynthetic pathways. This begins to answer the long-standing question as to how the same starting molecule can be converted into different products by enzymes that look strikingly similar,” said Rodney E. Kellems, Ph.D., professor and chairman of the Department of Biochemistry & Molecular Biology at the UT Medical School at Houston.
The study dispels the earlier view that these flavor-producing enzymes are only found in plants, Raman said. “We have discovered that they are also present in marine animals, such as sea anemone and corals. However, we do not know what they do in these organisms."
The study is titled “Structural insights into the evolutionary paths of oxylipin biosynthetic enzymes.” The lead authors were Dong-Sun Lee, Ph.D., an assistant professor in the Department of Biochemistry & Molecular Biology at the UT Medical School at Houston, and Pierre Nioche, Ph.D., an assistant professor at the Université Paris Descartes. Mats Hamberg, M.D., Ph.D., professor of medical chemistry in the Division of Physiological Chemistry, Karolinska Institutet, Stockholm, Sweden, collaborated on the research.
The research is supported by Pew Charitable Trusts through a Pew Scholar Award, The Robert A. Welch Foundation, The National Institutes of Health, a Beginning Grant in Aid from the American Heart Association, and an INSERM Avenir Grant sponsored by La Fondation pour la Recherche Medicale.
Rob Cahill | Newswise Science News
Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München
Second research flight into zero gravity
21.10.2016 | Universität Zürich
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences