March 12, 2013
Proteins In Extreme Bacteria Could Enable Life On Mars
Brett Smith for redOrbit.com - Your Universe Online
By studying microrganisms that thrive in the extreme environment of Antarctica, scientists from the University of Maryland have found new aspects of certain proteins that could enable life to function on Mars and in other extreme environments.
According to their report in the journal BMC Biotechnology, the scientists found significant differences in the core proteins of Antarctic extremeophile bacteria known as Haloarchaea, when compared to similar proteins in other microorganisms. These differences allow the extremeophiles to tolerate severe conditions such as extreme temperatures and high salt concentrations.
"In such cold temperatures, the packing of atoms in proteins must be loosened slightly, allowing them to be more flexible and functional when ordinary proteins would be locked into inactive conformations" said lead author Shiladitya DasSarma, from the Department of Microbiology and Immunology at the University of Maryland.
"The surface of these proteins also have modifications that loosen the binding of the surrounding water molecules."
One of the most notable differences found in the Haloarchaeal proteins is their acidity, caused by a molecular surface that is covered with negatively charged particles. This is quite different from the proteins found in most organisms, which are typically neutral. The researchers say the negative charges allow the organisms´ proteins to stay in solution and hold on tightly to water, reversing the effects of a high salinity habitat which would usually cause water within the cell to exit into the surrounding environment through the process of osmosis.
Another key protein feature was found in an Antarctic bacteria species named“¯Halorubrum lacusprofundi, which were collected from the continent´s highly salty Deep Lake. Because of the lake´s high salt concentration, its water stays in its liquid phase well below 32 degrees Fahrenheit. The unique makeup of the extremeophile´s proteins allows its enzymes to work in both cold and salty conditions.
"These kinds of adaptations are likely to allow microorganisms like“¯Halorubrum lacusprofundi to survive not only in Antarctica, but elsewhere in the universe," DasSarma said. "For example, there have been recent reports of seasonal flows down the steep sides of craters on Mars suggesting the presence of underground brine pools. Whether microorganisms actually exist in such environments is not yet known, but expeditions like NASA's Curiosity rover are currently looking for signs of life on Mars."
"Dr. DasSarma and his colleagues are unraveling the basic building blocks of life," added Dr. E. Albert Reece, dean of the University of Maryland´s School of Medicine, who was not directly involved in the study. "Their research into the fundamentals of microbiology are enhancing our understanding of life throughout the universe, and I look forward to seeing further groundbreaking discoveries from their laboratory."
Besides looking for extremeophiles on Mars, the authors also noted that the presence of frozen ice and water on Juptier´s moon Europa could also contain the ideal conditions for these unusual microorganisms.
In their report, the research team noted that the study´s findings could have implications for industrial and biotech processes as well. As an example, they said that these tough survival proteins could convey the extremeophile´s abilities to other enzymes and hydrocarbon solutions.
Besides being able to survive extreme conditions, many species of Haloarchaea“¯are capable of taking on a range of cellular shapes.