Hx-amides are fluorescent hybrids of imidazole (I)- and pyrrole (P)-containing polyamides and Hoechst 33258, and they bind in the minor groove of specific DNA sequences. Synthesis and DNA binding studies of HxII (5) complete our studies on the first set of Hx-amides: Hx-I/P-I/P. HxPP (2), HxIP (3) and HxPI (4) were reported earlier. Results from DNase I footprinting, biosensor-SPR, CD and ΔTM studies showed that Hx-amides interacted with DNA via the anti-parallel and stacked, side-by-side motif. Hx was found to mimic the DNA recognition properties of two consecutive pyrrole units (PP) in polyamides. Accordingly, the stacked Hx/PP pairing binds preferentially to two consecutive AT base pairs, A/T-A/T; Hx/IP prefers C-A/T; Hx/PI prefers A/T-C; and Hx/II prefers C-C. The results also showed that Hx-amides bound their cognate sequence at a higher affinity than their formamido-triamide counterparts.
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http://dx.doi.org/10.1016/j.bmcl.2013.01.075 | DOI Listing |
Bioorg Med Chem Lett
September 2021
Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, London WC1E 6BT, United Kingdom.
Five X-HxIP (Hx-amides) 6a-e, in which the N-terminus p-anisyl moiety is modified, were designed and synthesised with the purpose of optimising DNA binding, improving cellular uptake/nuclear penetration, and enhancing the modulation of the topoisomerase IIα (TOP2A) gene expression. The modifications include a fluorophenyl group and other heterocycles bearing different molecular shapes, size, and polarity. Like their parent compound HxIP 3, all five X-HxIP analogues bind preferentially to their cognate sequence 5'-TACGAT-3', which is found embedded on the 5' flank of the inverted CCAAT box-2 (ICB2) site in the TOP2A gene promoter, and inhibit protein complex binding.
View Article and Find Full Text PDFChembiochem
September 2018
Department of Chemistry, Georgia State University, 50 Decatur Street SE, Atlanta, GA, 30303, USA.
DNA minor groove binding polyamides have been extensively developed to control abnormal gene expression. The establishment of novel, inherently fluorescent 2-(p-anisyl)benzimidazole (Hx) amides has provided an alternative path for studying DNA binding in cells by direct observation of cell localization. Because of the 2:1 antiparallel stacking homodimer binding mode of these molecules to DNA, modification of Hx amides to 2-(p-anisyl)-4-azabenzimidazole (AzaHx) amides has successfully extended the DNA-recognition repertoire from central CG [recognized by Hx-I (I=N-methylimidazole)] to central GC [recognized by AzaHx-P (P=N-methylpyrrole)] recognition.
View Article and Find Full Text PDFBioorg Med Chem Lett
September 2015
Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, London WC1E 6BT, UK.
The design, synthesis, and DNA binding properties of azaHx-PI or p-anisyl-4-aza-benzimidazole-pyrrole-imidazole (5) are described. AzaHx, 2-(p-anisyl)-4-aza-benzimidazole-5-carboxamide, is a novel, fluorescent DNA recognition element, derived from Hoechst 33258 to recognize G·C base pairs. Supported by theoretical data, the results from DNase I footprinting, CD, ΔT(M), and SPR studies provided evidence that an azaHx/IP pairing, formed from antiparallel stacking of two azaHx-PI molecules in a side-by-side manner in the minor groove, selectively recognized a C-G doublet.
View Article and Find Full Text PDFBioorg Med Chem Lett
March 2013
Division of Natural & Applied Sciences and Department of Chemistry, Hope College, Holland, MI 49423, USA.
Hx-amides are fluorescent hybrids of imidazole (I)- and pyrrole (P)-containing polyamides and Hoechst 33258, and they bind in the minor groove of specific DNA sequences. Synthesis and DNA binding studies of HxII (5) complete our studies on the first set of Hx-amides: Hx-I/P-I/P. HxPP (2), HxIP (3) and HxPI (4) were reported earlier.
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