Comparison of various procedures for removing proteins and nucleic acids from cell walls of Bacillus subtilis

Several procedures were used in an attempt to prepare clean cell walls from Bacillus subtilis. The results indicate that protein and nucleic acids are tightly bound to the walls. The cleanest wall preparations were found following trichloroacetic acid extraction at 60 degrees or by extraction with 0.1N NaOH under a nitrogen atmosphere for 10 hrs. Protein denaturants, such as sodium dodecyl sulfate and concentrated guanidine hydrochloride were relatively ineffective in removing proteins and nucleic acids from the cell walls. Cell wall-bound DNA was biologically active in transformation assays.