Directed evolution of ligand dependence: small-molecule-activated protein splicing. Buskirk AR, Ong YC, Gartner ZJ, Liu DR. Directed evolution of ligand dependence: small-molecule-activated protein splicing. Proc Natl Acad Sci U S A. 2004;101(29):10505-10. doi:10.1073/pnas.0402762101 Read more