For a long time, textbooks have generally assumed that “an enzyme-substrate (ES) complex contains all components necessary for catalysis and that conversion to products occurs by rearrangement of atoms, protons, and electrons”. However, Yang and her colleagues by using time-resolved x-ray crystallography found that “the capture of a third Mg2+ is essential for catalyzing DNA synthesis”. (For detailed information, please check Gao, Y. & Yang, W. (2016) Capture of a third Mg2+ is essential for catalyzing DNA synthesis, Science, 352, 1334-1337, and A new paradigm of DNA synthesis: three-metal-ion catalysis.Yang W, Weng PJ, Gao Y.Cell Biosci. 2016 Sep 6;6(1):51. doi: 10.1186/s13578-016-0118-2. eCollection 2016. Review.) 

The findings by Yang’s team will have far-reaching significance in the understanding of the mechanisms of enzyme reactions, structure-based design (small molecule inhibitor of enzymes), and computational biochemistry.