* Corresponding authors

^a UCSF/UC Berkeley Joint Graduate Group in Bioengineering, University of California, Berkeley, California 94720, USA
E-mail: rich@zinc.cchem.berkeley.edu
Fax: +1-510-642-3599
Tel: +1-510-642-4192

^b Department of Chemistry, University of California, Berkeley, California 94720, USA
E-mail: francis@cchem.berkeley.edu
Fax: +1-510-643-3079
Tel: +1-510-643-9915

^c Department of Molecular and Cell Biology and Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA

^d The Molecular Foundry, Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

^e Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.