BENT DNA IS FOUND IN SOME, BUT NOT ALL, REGIONS RECOGNIZED BY THE BACILLUS-SUBTILIS ABRB PROTEIN

The AbrB protein of Bacillus subtilis is a transcriptional regulator o f numerous genes in diverse metabolic pathways that commence expressio n at the onset of stationary phase. AbrB is a DNA-binding protein with specific affinity for defined DNA regions of its target genes. Analys is of these regions has failed to detect a readily apparent sequence d eterminant for AbrB binding and it is believed that AbrB recognizes a specific DNA structure formed by a finite subset of base sequences. We have examined six AbrB binding regions for intrinsic bending and foun d that three do not contain a detectable intrinsic bend, whereas three do. AbrB binding to these regions resulted in electrophoretic mobilit y patterns that were consistent with, but did not prove, that the DNA moieties were present in a bent configuration.