Evidence map›Paper›PMID 42376817›Full record

ArticleNucleic acids research2026

Accessibility of telomeric overhangs to stabilizing small-molecule ligands.

Janan Alfehaid, Vidsara Surasinghe, Sineth G Kodikara, Mohammad L Kabir, Sajad Shiekh, Masayuki Tera, Kazuo Nagasawa, John J Portman, Hamza Balci

Abstract read
In one paragraph

Article in Nucleic acids research, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Review
4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

9 authors.

Janan AlfehaidDepartment of Physics, Kent State University, Kent, OH 44242, United States.
Vidsara SurasingheDepartment of Physics, Kent State University, Kent, OH 44242, United States.
Sineth G KodikaraDepartment of Physics, Kent State University, Kent, OH 44242, United States.
Mohammad L KabirDepartment of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, United States.
Sajad ShiekhDepartment of Physics, Kent State University, Kent, OH 44242, United States.
Masayuki TeraDepartment of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Tokyo, 183-8509, Japan.ORCID 0000-0003-4430-579X
Kazuo NagasawaDepartment of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Tokyo, 183-8509, Japan.
John J PortmanDepartment of Physics, Kent State University, Kent, OH 44242, United States.
Hamza BalciDepartment of Physics, Kent State University, Kent, OH 44242, United States.ORCID 0000-0002-0273-4871

Funding

Deanship of Scientific Research at Northern Border University SAFIR-2026NIH HHS 1R35GM156183
6 · The paper itself

Abstract

Human chromosomes terminate in 50-300 nucleotide (nt) long single-stranded telomeric overhangs composed of repeating d(TTAGGG) sequences, which can fold into tandem G-quadruplex (GQ) structures protecting chromosome ends. Stabilizing GQs by small-molecules inhibits telomerase, motivating development of GQ-targeting anti-cancer agents. However, how interactions among successive GQs and bound ligands affect small-molecule accessibility remain unclear. We used single-molecule fluorescence microscopy and stepwise photobleaching to quantify binding stoichiometry of fluorescent oxazole telomestatin derivative L1Cy5-7OTD to telomeric overhangs capable of forming 1-6 GQs (30-162 nt long), spanning much of the physiologically relevant range. Longer overhangs bound more ligands on average but consistently below the theoretical maximum, saturating at six ligands even when 12 binding sites were available. Increasing the inter-GQ spacer from 3-nt to 9-nt enhanced ligand binding, a result independently confirmed by ensemble fluorescence enhancement experiments using N-methyl mesoporphyrin IX as a ligand. A one-dimensional lattice model, describing equilibrium ligand binding to partially ordered telomeric overhangs, revealed positive cooperativity between folding of successive GQs, negative cooperativity between ligands bound opposing (top and bottom) faces of successive GQs, and reduced affinity at duplex-single strand junction. These results show how telomeric architecture governs ligand accessibility and inform rational GQ-targeted drug design.

Indexed as

G-QuadruplexesTelomereFluorescent DyesHumansLigandsMicroscopy, FluorescenceOxazolesTelomeraseFluorescent DyesLigandsOxazolesTelomerasetelomestatin

Identifiers

PMID42376817
PMCPMC13316431

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.