Nature Chemistry 6, 1044–1048 (2014); published online 2 November 2014; corrected after print 20 November 2014.

In the version of this Article originally published, the list of author affiliations was incomplete, and should have appeared as shown below. The list has been corrected in the online versions of the Article.

Lee-Ping Wang1,2, Alexey Titov1,2 †, Robert McGibbon2, Fang Liu1,2, Vijay S. Pande2 and Todd J. Martínez1,2,3*

1The PULSE Institute, Stanford University, Stanford, California 94305, USA. 2Department of Chemistry, Stanford University, Stanford, California 94305, USA. 3SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA. Present address: Advanced Micro Devices, Sunnyvale, California 94088, USA. *e-mail: toddjmartinez@gmail.com