Structural highlights
Publication Abstract from PubMedThe final 3'-terminal residue of the telomeric DNA G-overhang is inherently less precise. Here, we describe how alteration of the last 3'-terminal base affects the mutual recognition between two different G-rich oligomers of human telomeric DNA in the formation of heteromolecular G-quadruplexes (hetero-GQs). Associations between three- and single-repeat fragments of human telomeric DNA, target d(GGGTTAGGGTTAGGG) and probe d(TAGGGT), in Na+ solution yield two coexisting forms of (3 + 1) hybrid hetero-GQs: the kinetically favourable LLP-form (left loop progression) and the thermodynamically controlled RLP-form (right loop progression). However, only the adoption of a single LLP-form has been previously reported between the same probe d(TAGGGT) and a target variant d(GGGTTAGGGTTAGGGT) having one extra 3'-end thymine. Moreover, the flanking base alterations of short G-rich probe variants also significantly affect the loop progressions of hetero-GQs. Although seemingly two pseudo-mirror counter partners, the RLP-form exhibits a preference over the LLP-form to be recognized by a low equivalent of fluorescence dye thioflavin T (ThT). To a greater extent, ThT preferentially binds to RLP hetero-GQ than with the corresponding telomeric DNA duplex context or several other representative unimolecular GQs. Two coexisting pseudo-mirror heteromolecular telomeric G-quadruplexes in opposite loop progressions differentially recognized by a low equivalent of Thioflavin T.,Fu W, Jing H, Xu X, Xu S, Wang T, Hu W, Li H, Zhang N Nucleic Acids Res. 2021 Oct 11;49(18):10717-10734. doi: 10.1093/nar/gkab755. PMID:34500466[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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