Portable gas sensors can allow you to search for explosives, diagnose medical conditions through a patient's breath, and decide whether it's safe to stay in a mine. These devices do all this by identifying and measuring airborne chemicals, and a new, more sensitive, smart model is under dev ... more
Vitamins doing gymnastics: Scientists capture first full image of vitamin B12 in action
Work by University of Michigan and MIT team yields new understanding of crucial reaction in the body and in CO2-scrubbing bacteria
28-03-2012: You see it listed on the side of your cereal box and your multivitamin bottle. It's vitamin B12, part of a nutritious diet like all those other vitamins and minerals. But when it gets inside your body, new research suggests, B12 turns into a gymnast.
In a paper published in Nature, scientists from the University of Michigan Health System and the Massachusetts Institute of Technology report they have created the first full 3-D images of B12 and its partner molecules twisting and contorting as part of a crucial reaction called methyltransfer.
That reaction is vital both in the cells of the human body and, in a slightly different way, in the cells of bacteria that consume carbon dioxide and carbon monoxide. That includes bacteria that live in the guts of humans, cows and other animals, and help with digestion. The new research was done using B12 complexes from another type of carbon dioxide-munching bacteria found in the murky bottoms of ponds.
The 3-D images produced by the team show for the first time the intricate molecular juggling needed for B12 to serve its biologically essential function. They reveal a multi-stage process involving what the researchers call an elaborate protein framework – a surprisingly complicated mechanism for such a critical reaction.
U-M Medical School professor and co-author Stephen Ragsdale, Ph.D., notes that this transfer reaction is important to understand because of its importance to human health. It also has potential implications for the development of new fuels that might become alternative renewable energy sources.
"Without this transfer of single carbon units involving B12, and its partner B9 (otherwise known as folic acid), heart disease and birth defects might be far more common," explains Ragsdale, a professor of biological chemistry. "Similarly, the bacteria that rely on this reaction would be unable to consume carbon dioxide or carbon monoxide to stay alive – and to remove gas from our guts or our atmosphere. So it's important on many levels."
In such bacteria, called anaerobes, the reaction is part of a larger process called the Wood-Ljungdahl pathway. It's what enables the organisms to live off of carbon monoxide, a gas that is toxic to other living things, and carbon dioxide, which is a greenhouse gas directly linked to climate change. Ragsdale notes that industry is currently looking at harnessing the Wood-Ljungdahl pathway to help generate liquid fuels and chemicals.
In the images created by the team, the scientists show how the complex of molecules contorts into multiple conformations - first to activate, then to protect, and then to perform catalysis on the B12 molecule. They had isolated the complex from Moorella thermoacetica bacteria, which are used as models for studying this type of reaction.
The images were produced by aiming intense beams of X-rays at crystallized forms of the protein complex and painstakingly determining the position of every atom inside.
"This paper provides an understanding of the remarkable conformational movements that occur during one of the key steps in this microbial process, the step that involves the generation of the first in a series of organometallic intermediates that lead to the production of the key metabolic intermediate, acetyl-CoA," the authors note.
Senior author Catherine L. Drennan from MIT and the Howard Hughes Medical Institute, who received her Ph.D. at the U-M Medical School, adds, "We expected that this methyl-handoff between B vitamins must involve some type of conformational change, but the dramatic rearrangements that we have observed surprised even us."
- University of Michigan
- x-ray diffraction
Nerve gases are colorless, odorless, tasteless and deadly. While today's soldiers carry masks and other protective gear, they don't have reliable ways of knowing when they need them in time. That could change, thanks to a new litmus-like paper sensor made at the University of Michigan.The p ... more
Using a new gene-editing system based on bacterial proteins, MIT researchers have cured mice of a rare liver disorder caused by a single genetic mutation. The findings, described in Nature Biotechnology, offer the first evidence that this gene-editing technique, known as CRISPR, can reverse ... more
Light waves can be defined by three fundamental characteristics: their color (or wavelength), polarization, and direction. While it has long been possible to selectively filter light according to its color or polarization, selectivity based on the direction of propagation has remained elusi ... more
Small protein fragments, also called peptides, are promising as drugs because they can be designed for very specific functions inside living cells. Insulin and the HIV drug Fuzeon are some of the earliest successful examples, and peptide drugs are expected to become a $25 billion market by ... more
- 1Schleicher & Schuell has been purchased by Whatman plc
- 2The shadow of a disease
- 3Bibby Scientific Ltd acquires PCRmax Ltd
- 4A Breakthrough in Electron Microscopy
- 5Merck to Acquire Sigma-Aldrich to Enhance Position in Attractive Life Science Industry
- 6LGC rebrands reference standards
- 7VWR International, LLC Signs Agreement to Acquire Peqlab Biotechnologie GmbH
- 8Gilson announces the acquisition of Armen
- 9LGC extends forensic and paternity DNA operations into Europe
- 10analytica China 2014: Closed with overall success
- New sequencing reveals genetic history of tomatoes
- New blood test determines whether you have or are likely to get cancer
- Yale University and Leica Microsystems Partner to Establish Microscopy Center of Excellence
- Graphene imperfections key to creating hypersensitive 'electronic nose'
- Large study reveals new genetic variants that raise risk for prostate cancer