Figure 5
NMR titration of MtHigA335–117 and its promoter DNA. (a) Overlaid [1H-15N] TROSY–HSQC titration spectra of 0.4 mM 15N-labelled MtHigA335–117 with increasing concentrations of promoter DNA. (b) CSP analysis of MtHigA335–117 upon binding to the promoter DNA. CSPs > average CSP values (0.075) are coloured cyan, CSPs < average CSP values (0.075) are coloured grey, and the peaks that disappeared upon the addition of DNA are presented as magenta bars. Secondary structural elements of MtHigA335–117 are represented above the plot by blue cylinders (α-helices) and yellow arrows (β-strands). (c) The residues showing higher CSP values than the average CSP value in the β-lid (His93, Leu84, Ala98 and Val105) are shown as sticks and coloured cyan in the box. For a clear display, MtHigA3 bound to DNA is presented as a cartoon diagram in surface view (left). Chemical shift mapping based on the CSP data from (b) on the crystal structure of MtHigA3 bound to DNA in two orientations rotated by 90°. The DNA structure is represented using sticks for clarity. |