Resuspend cells in 400 ul TES (50 mM Tris-HCl, 10 mM NaCl, 10 mM EDTA, pH7.5).
Add: 17 ul 30% (w/v) sarkosyl (final concentration of 1%) and 5 ul 10 mg/ml proteinase K (final concentration 100 ug/ml).
Incubate at 37C for 30-60 minutes, or until the solution clears.
Add 400 ul 4 M NH4OAc and mix well.
Resuspend pellet in 400 ul 0.1 M NaOAc pH 6.0. Pellet may not resuspend completely. Reprecipitate DNA with 800 ul EtOH for 15 minutes at RT.
Resuspend DNA in 50 ul TE (10 mM Tris pH 8.0, 0.1 mM EDTA) overnight at 4C. May add 1 ul RNase to help DNA dissolve. Yields 25-50 ug of DNA; use 1-5 ul per digest.