Some of the world's tiniest organisms may have a large impact on climate change.
Researchers from the U.S. Department of Energy's Argonne National Laboratory and the University of Tennessee found that microorganisms called archaea living in marine sediments use completely novel enzymes to break down organic matter into carbon dioxide.
An Argonne/University of Tennessee research team reconstructed the crystal structure of BAP, a protein involved in the process by which marine archaea release carbon, to determine how it functioned, as well as its larger role in carbon cycling in marine sediments. Research was performed at the Advanced Photon Source and the Advanced Protein Characterization Facility.
Image courtesy Andrzej Joachimiak/Argonne National Laboratory
These single-celled archaea eat organic carbon in marine sediments. Enzymes in the archaea break down large carbon molecules into smaller units. This process releases carbon dioxide and methane into the water and eventually, into the atmosphere.
However, as the temperature of oceans and bodies of freshwater increases, this carbon cycling process accelerates. The temperature at the bottom of the ocean, for example, is approximately two to four degrees Celsius (35 to 39 degrees Fahrenheit). According to Andrzej Joachimiak, Argonne distinguished fellow and director of the Structural Biology Center, if the ocean temperature rises one or two degrees, the rate of carbon release might increase.
"About 40 percent of Earth's organic carbon is stored in marine sediments," Joachimiak said. "An increase in temperature and acceleration of the carbon cycling process in these sediments is a major concern."
Joachimiak said scientists are uncertain about how fast archaea process carbon and whether the release is accelerating. Once researchers have these statistics, they may find ways to better predict the environment's response to a changing climate.
This understanding starts at the molecular level. Using resources at the Advanced Photon Source, a DOE Office of Science User Facility, and the Advanced Protein Characterization Facility, the research team produced and crystallized bathyaminopeptidase, or BAP - one of the enzymes found in the archaea - to look into its structure and observe how it operates. They found that BAP plays an important role in breaking down proteins and, consequently, the turnover of atmospheric carbon.
The biggest challenge the researchers had was determining BAP's function, because no previously cultured organisms shared a close ancestry. These types of organisms are considered microbial "dark matter" because their physiologies are unknown and they have never been grown in a lab.
And because it is difficult to study their physiologies, scientists cannot determine their precise impact on ecosystems and major global events. For example, BAP was found to be structurally similar to the known amino acid ester hydrolase, but had evolved to serve an entirely different function.
Despite this challenge, the researchers demonstrated that detailed characterization of enzymes from microbial dark matter can be done without first having to grow those organisms in the lab, which may be difficult or time-consuming.
"Being able to characterize proteins directly from microbial dark matter, without requiring that they first be grown in a lab, opens up limitless possibilities for discovering novel functions of these strange organisms that control the breakdown of carbon in marine sediments," said Karen Lloyd, assistant professor in the department of microbiology at the University of Tennessee.
According to Karolina Michalska, assistant protein crystallographer in the Biosciences Division, it was originally believed that bacteria were the primary players in the degradation of proteins in marine sediments. But the research shows that archaea are also involved in the process.
"It seems that archaea have a larger role in organic carbon, or protein, degradation than we previously realized," Michalska said.
The study, "New aminopeptidase from 'microbial dark matter' archaeon," was published June 10 in The FASEB Journal. The research was supported by the U.S. Department of Energy's Office of Science, by the U.S. National Institutes of Health and by the Center for Dark Energy Biosphere Investigations led by the University of Southern California. Studies were performed at the 19-Insertion Device Beamline, operated by the Structural Biology Center at the Advanced Photon Source at Argonne, and at Argonne's Advanced Protein Characterization Facility.
Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy's Office of Science.
The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
Brian Grabowski | EurekAlert!
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
19.07.2018 | Materials Sciences
19.07.2018 | Earth Sciences
19.07.2018 | Life Sciences