1 MIT Microbiology Program, Massachusetts Institute of Technology, Cambridge, MA, United States; MIT Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA, United States; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States; Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States; Harvard Biophysics Program, Harvard University, Boston, MA, United States; Broad Institute of MIT and Harvard, Cambridge, MA, United States. Electronic address: timlu@mit.edu.
2 Department of Environmental Health Sciences, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States. Electronic address: chandra@jhmi.edu.
3 Journal of Molecular Biology, Cambridge, MA, United States. Electronic address: h.hodak@elsevier.com.