Electrophoretic mobility shift assay for AirR. The first lane was the free DNA probe (2 nM); the second to fourth lanes were the DNA probe with increasing amounts of AirR (0.3, 0.6, and 1.2 μM); the fifth lane was the same as the fourth lane but with the addition of a 50-fold excess of unlabeled probes as specific competitors (SCs). The sixth lane was as the same as the fourth lane but with the addition of a 50-fold excess of unlabeled pta ORF region fragments as non-specific competitor. (NC). (a) EMSA with cap promoter; (b) ddl promoter; (c) pbp1 promoter; (d) lytM promoter.