SEP 07, 2017 6:00 AM PDT

Surprise! Sugar Molecules Can Form Rigid Structures After all

WRITTEN BY: Daniel Duan

An oligosaccharide is a small polymer that typically has three to ten individual sugar molecules. Most naturally occurring oligosaccharides can be found in plants. For example, Raffinose, a trisaccharide consisting of galactose, glucose, and fructose, are present in vegetables like beans, cabbage, and brussels sprouts. Oligosaccharides can form conjugates by bonding to amino acid side-chains in proteins or to lipid moieties. Oligosaccharides and their conjugates have many functions in human body. Glycolipids the sugar-coupled fat molecules on the outer cellular membrane can help immune system distinguish the body's own cells from pathogens or other foreign cells. Nutrients wise, oligosaccharides are considered one of the main source of prebiotics. Prebiotics are the broken-down food components that support the growth of certain beneficial bacteria in the colon.

The oligosaccharide that comprises three sugars can form a rigid structure, thanks to a hydrogen bond (dotted line) between Carbon-Hydrogen bond in the upper molecule (red) and Oxygen between two Carbons in the lower molecule (yellow).

Credit: Chemistry

Oligosaccharides were previously thought to be flexible. The individual sugar molecules in the chain are supposed to behave like beads on a string: they can rotate on their position as long as their functional groups do not hinder the motion. Many naturally existing polymers of amino acids or nucleotides cannot do the same - different units within the polymer chain can form hydrogen bond(s), resulting in the so-called secondary structures. These structures are three-dimensional formations, such as the double helix in DNAs or the spirals and pockets in proteins.

Recently the discovery made by an international research team has changed this assumption. Using NMR structure determination and database searches, the researchers identified numerous trisaccharide polymers, all of which contain a fucose, can form a non-conventional C−H⋅⋅⋅O hydrogen bond, which gives these polymers a characteristic rigidity. What is more important, these trisaccharides are the basic building blocks in numerous classes of oligosaccharides found in everything from bacteria to mammals.

This finding disproves a long-standing dogma that the hydrogen bonds between oligosaccharide building blocks are too weak to form any secondary structure. "Our work now shows that certain hydrogen bonds have to be taken into account. As a slight tip of the scales, they can help significantly in forcing the sugar building blocks into a rigid corset," says Dr. Mario Schubert, the head of the research team and a structural biologist at the University of Salzburg. "Oligosaccharides with the newly discovered structural pattern are recognized easily by other molecules using the lock and key principle because a rigid, inflexible structure simplifies molecular recognition." He hopes that their discovery can help to better understand the interactions between oligosaccharides-bearing immune system molecules and stem cells.

Biochemistry of Carbohydrate. Credit: Armando Hasudungan

Source: Chemistry / Phys.org

About the Author
  • Graduated with a bachelor degree in Pharmaceutical Science and a master degree in neuropharmacology, Daniel is a radiopharmaceutical and radiobiology expert based in Ottawa, Canada. With years of experience in biomedical R&D, Daniel is very into writing. He is constantly fascinated by what's happening in the world of science. He hopes to capture the public's interest and promote scientific literacy with his trending news articles. The recurring topics in his Chemistry & Physics trending news section include alternative energy, material science, theoretical physics, medical imaging, and green chemistry.
You May Also Like
OCT 16, 2020
Chemistry & Physics
The "Missing" Laureate at 2020 Physics Nobel
OCT 16, 2020
The "Missing" Laureate at 2020 Physics Nobel
Last week, the science community celebrated the awarding of this year's Nobel Physics Prize to a trio of black hole ...
OCT 22, 2020
Chemistry & Physics
NASA Looks to Nuclear Fusion for Powering Deep Space Missions
OCT 22, 2020
NASA Looks to Nuclear Fusion for Powering Deep Space Missions
Nuclear fusion is the frontier of energy research, and NASA has a plan to bring this state-of-the-art power source to th ...
OCT 23, 2020
Chemistry & Physics
Expanding on Einstein's theory of time dilation
OCT 23, 2020
Expanding on Einstein's theory of time dilation
Research published recently in the journal Nature Communications considers the influence of the quantum mechanics c ...
OCT 30, 2020
Chemistry & Physics
Designing tensional homeostasis in human skin equivalents
OCT 30, 2020
Designing tensional homeostasis in human skin equivalents
A new development in the production of artificial skins comes from scientists at the RIKEN Center for Biosystems Dynamic ...
NOV 02, 2020
Space & Astronomy
Never-Found-Before Molecule Detected in Titan's Atmosphere
NOV 02, 2020
Never-Found-Before Molecule Detected in Titan's Atmosphere
Astronomers have detected Cyclopropenylidene (C3H2) on Titan, one of Saturn's 53 confirmed moons. While the molecule ...
NOV 10, 2020
Chemistry & Physics
Are PBDEs in your house? Understanding the impacts of PBDE chemicals on the development of diabetes
NOV 10, 2020
Are PBDEs in your house? Understanding the impacts of PBDE chemicals on the development of diabetes
New research from UC Riverside conducted on animal models suggests that maternal exposure to common flame retardants cal ...
Loading Comments...