Negative plus
For years, researchers have worked to develop novel molecules for therapeutic or research purposes, and have relied on directed evolution as a powerful technique for generating molecules that exhibit the properties they want. Led by David Liu, a professor of chemistry and chemical biology and a Howard Hughes Medical Institute investigator, a team of Harvard researchers recently developed the first system for enabling proteins to evolve continuously in the laboratory, without researcher intervention. That system, called PACE (phage-assisted continuous evolution), allowed for protein evolution to take place approximately 100 times faster than previously possible. Now Liu and colleagues have added a powerful new tool to their arsenal — the ability to eliminate molecules they don’t want during continuous directed evolution. The researchers have equipped PACE with a negative selection — the ability to drive evolution away from certain traits — to enable the rapid evolution of molecules with dramatically altered properties. That ability,...