Figure 3: Phosphorylated OmpR binds to the promoter region of mcpM.
From: Microcin PDI regulation and proteolytic cleavage are unique among known microcins
(A) Electrophoretic mobility shift assays (EMSA) of a 200 bp DNA fragment located at position from −10 bp to −210 bp relative to the start codon of mcpM gene (Pmic-10/−210). DNA (80 ng) was mixed with recombinant OmpR (0, 75, 150, 300, 600, 900 ng) or with an unrelated protein (XRE; Xenobiotic Response Element). (B) Unphosphorylated OmpR (Lane 2-Lane 6) for which the phosphorylation site (D55) was replaced by alanine and the protein no longer binds to Pmic-10/−210. Normal OmpR (Lane 7 and 8) was included as control. (C) OmpR expressed and purified from BL21(DE3) in M9 broth (Lane 2- Lane 6) exhibited limited binding to Pmic-10/−210.
