Two coexisting pseudo-mirror heteromolecular telomeric G-quadruplexes in opposite loop progressions differentially recognized by a low equivalent of Thioflavin T. Issue 18 (9th September 2021)

• Record Type: Journal Article
• Authors: Fu, Wenqiang; Jing, Haitao; Xu, Xiaojuan; Xu, Suping; Wang, Tao; Hu, Wenxuan; Li, Huihui; Zhang, Na
• Is Part Of: Nucleic acids research. Volume 49:Issue 18(2021)
• Page Start: 10717
• Page End: 10734
• Publication Date: 2021-09-09
• Subjects: Nucleic acids -- Periodicals; Molecular biology -- Periodicals; 572.805
• DOI: 10.1093/nar/gkab755
• Languages: English
• ISSNs: 0305-1048

Abstract

Abstract: The 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(GGGTTAGGGTTAGGG T ) 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.