Fig. 2
From: Binding site of restriction-modification system controller protein in Mollicutes
Binding site of HsdC. a – structure of hsd operon promoter and the diversity of operons controlled by its homologs in Mollicutes. The HsdC binding site overlaps with the -10 box and the transcription start site (promoter data were taken from [1]). Orange boxes on operons diagram show HsdC-binding repeats. b – EMSA of HsdC with a set of oligos including wild-type promoter of hsd operon, mutated variants and MraZ regulator binding site. PhsdCWT- – free oligo with hsd operon promoter sequence, PmraZWT- – free oligo with DCW operon promoter sequence, Neg – control oligo without HsdC binding site, PhsdCWT+ – hsd operon promoter with HsdC protein, Mut1-6 – mutated hsd operon promoter with HsdC protein (sequences shown below), PmraZ HsdC – DCW operon promoter with HsdC protein, Neg HsdC – control oligo with HsdC protein, PmraZ MraZ – DCW cluster operon promoter with MraZ protein (as control), PhsdC MraZ – hsd operon promoter with MraZ protein. c – fractional saturation of DNA of wild-type and mutated hsd operon promoter sequence. Sequences are shown on panel E. Data were calculated from EMSA gels. d – mutations introduced to hsd operon promoter to test HsdC specificity. e – sequence logo of HsdC binding site with direct repeats across the mycoplasmas. The most conserved TG dinucleotide plays the most important role in binding, as shown in A and B (Mut2 and Mut4 oligos)