1 Department of Chemistry and Courant Institute of Mathematical Sciences, New York University, New York, New York. Electronic address: schlick@nyu.edu.
2 Department of Biochemistry, Emory University, Atlanta, Georgia.
3 Department of Chemistry and Biochemistry, and Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma.
4 Department of Structural Biology and Center for Data Driven Discovery, St. Jude Children's Research Hospital, Memphis, Tennessee.