Isolation of the protein from the wild-type strain ISP794 binding to different fragments of the norA promoter. Different fragments of DNA were immobilized on magnetic beads. Proteins binding to these fragments were then used for different analyses. (A) SDS-PAGE analysis of protein released from DNA affinity magnetic beads. Lane 1, standard proteins (in kilodaltons); lane 2, fragment L2-R2; lane 3, fragment L1-R2; lane 4, fragment L2-R3. The 18-kDa protein is indicated by an arrow on the left. (B) Gel mobility shift analysis of fragment L2-R2 with affinity-purified extracts from strain ISP794. Lane 1, control DNA without protein; lane 2, purified protein; lane 3, 0.5 μg of protein from crude extracts of ISP794. Free DNA is indicated by an arrow.