American Chemical Society / Center for Single Molecule Biophysics / National Science Foundation / Arizona State UniVersity / Biodesign Institute / Histone H4-K16 Acetyl-Specific DNA Aptamer Berea A. R. Williams / † / § Liyun Lin / ‡ / | Stuart M. Lindsay / ‡ / | / § and John C. Chaput* / † / § Center for BioOptical Nanotechnology / Department of Chemistry and Biochemistry / Department of Physics / Center for BioOptical Nanotechnology / /