Copyright information:Taken from "Molecular recognition of DNA base pairs by the formamido/pyrrole and formamido/imidazole pairings in stacked polyamides"Nucleic Acids Research 2005;33(3):912-921.Published online 9 Feb 2005PMCID:PMC549405.© The Author 2005. Published by Oxford University Press. All rights reserved Also depicted in this figure is the range of binding constants (10–10 M) for the f/Im and f/Py terminal pairings when placed adjacent to –ImPy– and –PyPy– central pairings. The gray box indicates selective binding by f/Im to C/G and Xs denote the poor match of f/Py and the C/G base pair.