Image Credit: Sartorio et al., Acta Crystallographica Secton D Volume 77, Part 3, 369-379, March 2021
Using Crystal Screen, Mariana G. Sartorio, Néstor Cortez and Javier M. González crystallized, determined the structure of, and explored the structure and functional properties of the cold adapted catalase KatE1 from Acinetobacter sp. Ver3 native to the Atacama plateau in northern Argentina. Heme catalases remove hydrogen peroxide by catalyzing its dismutation into water and molecular oxygen, thereby protecting the cell from oxidative damage. The Atacama plateau in northern Argentina, located 4000 m above sea level, is a desert area characterized by extreme UV radiation, high salinity and a large temperature variation between day and night. The team present structural and functional evidence indicating that KatE1 is a highly active cold-adapted enzyme that is functional over a wide range of pH values and temperatures. They postulate that cold adaptation arises in part from the replacement of branched-chain amino acids by methionine residues, along with the customary structural features leading to increased flexibility at low temperatures.