Researchers here now have a picture of a key molecule that lets microbes produce carbon dioxide and methane – the two greenhouse gases associated with global warming.
The findings relate to organisms called methanogens and are explained in the latest issue of the journal
Proceedings of the National Academy of Sciences.
The publication capped a 12-year effort and can offer some insights into how industrial processes might be improved, explained Michael Chan, professor of biochemistry, and Joseph Krzycki, professor of microbiology, both of Ohio State University.
"This enzyme is the key to the whole process of methanogenesis from acetic acid," Krzycki said. "Without it, this form of methanogenesis wouldn't happen. Since it is so environmentally important worldwide, the impact of understanding this would be enormous."
Methanogenesis is the process by which the gas methane is made, and it takes place everywhere across the globe, from swamps to landfills, releasing the gas that ultimately seeps into the atmosphere.
One central player in this process is the microbe called Methanosarcina barkeri, a member of an unusual group of organisms called the Archaea that is similar to both bacterial and animal cells. This organism possesses large amounts of the enzyme so important for making methane.
"We often think only of humans putting carbon dioxide and methane into the atmosphere but natural biology itself actually provides its own sizeable share," said Chan. "This enzyme plays an important role in the process that converts acetate into these two gases."
The research can be traced to work that Krzycki did as a graduate student in the mid-1980s studying the protein known as acetyl-CoA decarbonylase/synthase (ACDS). He was focusing on whether carbon monoxide oxidation was part of the process of methanogenesis from acetate, which had not been suspected before.
In 1995, Chan approached Krzycki about working with this protein as one of the first projects Chan took on after coming to Ohio State. The goal was to use protein crystallography to get a picture of it and figure out how it works.
An important initial step in this kind of research is to "grow" crystals of the protein molecules, and from these crystals, scientists can actually map out the protein's structure.
"We tried for six months when I first arrived at Ohio State but at the end of that period, we couldn't get any crystals to grow," Chan said.
Two years later, Chan and a former graduate student, Bing Hao, went back to look at those previous crystallization experiments and discovered that crystals had eventually grown.
"The identification of these crystals allowed us to solve the structure of the protein making up the crystals, although it took 10 more years to do that," he said. "From the structure, we got a beautiful picture of the protein that we could use to understand how it works. Viewing a structure is somewhat like looking at the schematics of an engine."
Krzycki said that processes similar to those performed by this protein are currently being used in industry, although in those cases, high temperatures are required.
"From studying this process in these microbes, hopefully scientists can understand how their natural catalysts make this reaction work at lower temperatures," he said.
Source: Ohio State University
Related stories:
Liver cancer marker could yield blood test for early detection
In the face of an emerging liver cancer crisis in Asia, researchers at the Chinese University of Hong Kong have developed a test that could help millions. Due to widespread hepatitis B virus (HBV) infection, nearly 10 percent of China’s population is at high risk for hepatocellular carcinoma (HCC), a liver cancer with low survival rates if not detected and treated early. Researchers report on a new blood screening technique that could make it possible to detect early-stage liver cancer and predict how well a patient will do following treatment.
Ophthalmologists and physicists team up to design 'bionic eye'
Stanford physicists and eye doctors have teamed up to design a "bionic eye," of sorts. On Feb. 22 in the Journal of Neural Engineering, Daniel Palanker, Alexander Vankov and Phil Huie from the Department of Ophthalmology and the Hansen Experimental Physics Laboratory and Stephen Baccus from the Department of Neurobiology published a design of an optoelectronic retinal prosthesis system that can stimulate the retina with resolution corresponding to a visual acuity of 20/80--sharp enough to orient yourself toward objects, recognize faces, read large fonts, watch TV and, perhaps most important, lead an independent life. The researchers hope their device may someday bring artificial vision to those blind due to retinal degeneration.
New 'trick' allows HIV to overcome a barrier to infection
Researchers have discovered a new 'trick' that allows HIV to overtake resting T cells that are normally highly resistant to HIV infection, according to a report in the September 5th issue of the journal
Cell. The binding of the virus to the surface of those cells sends a signal that breaks down the cells' internal skeleton, a structure that otherwise may present a significant barrier to infection.
Fatal protein interactions may explain neurological diseases
In a collaborative study at the University of California, San Diego, investigators from neurosciences, chemistry and medicine, as well as the San Diego Supercomputer Center (SDSC) have investigated how proteins involved in neurodegenerative diseases such as Alzheimer's and Parkinson's disease interact to form unique complexes. Their findings explain why Alzheimer's patients might develop Parkinson's, and vice versa. The new and unique molecular structures they discovered can now be used to model and develop new drugs for these devastating neurological diseases. Their findings will be published in the September 3 issue of
Public Library of Science (PLoS) ONE on September 4, 2008.
Structure of key epigenetics component identified
Scientists from the Structural Genomics Consortium (SGC) have determined the 3D structure of a key protein component involved in enabling "epigenetic code" to be copied accurately from cell to cell.
Researchers offer first direct proof of how osteoarthritis destroys cartilage
A team of orthopaedic researchers has found definitive, genetic proof of how the most common form of arthritis destroys joint cartilage in nearly 21 million aging Americans, according to a study published online Sept. 2 in the
Journal of Bone and Mineral Research. The findings serve as an important foundation for the design of new treatments for osteoarthritis (OA), researchers said.
Study finds B-vitamin deficiency may cause vascular cognitive impairment
A deficiency of B-vitamins may cause vascular cognitive impairment, according to a new study. Researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University used an experimental model to examine the metabolic, cognitive, and microvascular effects of dietary B-vitamin deficiency. Their findings appear in the August 26, 2008 issue of
Proceedings of the National Academy of Sciences (PNAS).
Orienting Flow in Carbon Nanotubes
(PhysOrg.com) -- Carbon nanotubes provide some of the most interesting possibilities for future technology. One of the more intriguing possibilities – with a variety of practical applications – is using carbon nanotubes for water transport. In the past, experiments have suggested that extremely fast water transport can be attained through carbon nanotubes as small as two nanometers in diameter by applying a pressure gradient.