Binding of BAL 31 RNA polymerase to PM2 DNA as determined by electron microscopy and protection against restriction endonuclease cleavage.

Specific binding sites of BAL 31 RNA polymerase on PM2 DNA have been mapped by protection against HincII and HindIII cleavage and by observation of enzyme-DNA complexes by electron microscopy. Nine specific binding sites were observed at map units 0.19, 0.20, 0.28, 0.54, 0.63, 0.65, 0.71, 0.72, and 0.75 by the first method. All these sites were confirmed by electron microscopy which, in addition, revealed another site at 0.05 map unit. Published nucleotide sequences of the region surrounding sites at 0.71 and 0.75 map units show the presence of consensus sequences for procaryotic promoters.