Directed Evolution of Human Cu,Zn-SOD Under Artificial Oxidant Pressures

Cu,Zn-SOD is a highly conserved enzyme and the controversy about its evolutionary possibility in the near future has been lively. In order to further our understanding of the future fate of human Cu,Zn-SOD, we adopted a strategy relating to the directed evolution to study how the mutants of human Cu,Zn-SOD respond to different oxidative stress. After five rounds of screening, we found a mutant that can survive under harsh pressures and DNA sequencing proves that it shows a mutation responsible for the phenomenon. However, under natural pressure, our screening comes to nothing. Then we may draw the following conclusions: the evolution of biological macromolecules in some respect depends on their surroundings and if they are too familiar with a certain environment, they may embody evolutionary inertia.