The researchers around winter biochemist Escherichia coli have gradually grown through evolution over several years, a higher heat resistance: the bacteria now grow at temperatures of 48.5 degrees Celsius. Here, however, a natural limit seems to exist for the organism. Compared to the ancestors, the heat-resistant bacteria already contained the protein GroE known as heat protection in 16-fold higher concentrations under normal conditions. However, the heat resistance has its price: Since the organism carries changes in the genome due to the constant stress and puts a lot of energy into the production of heat protection proteins, it grows overall slower than its ancestors.
GroE belongs to the so-called chaperones: These proteins help freshly produced proteins to fold correctly. Each protein consists of a long chain of amino acids. Only through artistic folding into a three-dimensional structure does it become the functioning protein. In the case of the bacterium Escherichia coli, GroE solidified proteins that become unstable at higher temperatures and returned them to their functional form. "The ability of heat-resistant bacteria to produce significantly higher levels of GroE is a critical factor in survivability under these conditions, " explains Jeannette Winter.
The study also provides clues as to how organisms adapt to changing environmental conditions. This could open up new avenues for the targeted breeding of organisms for specific tasks: "These are not only bacteria for the production of pharmaceutically interesting proteins, but also, for example, bacteria that can break down environmental toxins under harsh environmental conditions, " explains Winter. displayJeannette Winter (Technical University of Munich) et al .: Journal of Biological Chemistry, doi: 10.1074 / bjc.M110.103374 ddp / science.de? Rochus Rademacher