Schematic representation of interactions between Δ19ω and DNA in Δ19ω-(→→) (left) and Δ19ω-(→←) (right)

Copyright information:Taken from "Structures of ω repressors bound to direct and inverted DNA repeats explain modulation of transcription"Nucleic Acids Research 2006;34(5):1450-1458.Published online 9 Mar 2006PMCID:PMC1401508.© The Author 2006. Published by Oxford University Press. All rights reserved The orientation of heptads is indicated by blue arrows and palindromic symmetry by the black ellipse. Yellow bases specifically interact with Δ19ω. Residues labeled green for Δ19ω A/B and black for Δ19ω A′/B′. Hydrogen bonds to phosphate oxygens (red) in thin black lines, specific hydrogen bonds to bases in the major groove in black arrows, blue lines indicate water (blue dots) mediated hydrogen bonds. K28 (K28′) and Arg31 (Arg31′) interact differently in subunits A/B and A′/B′.