biostudies-literatureYan ZNatural Science Foundation of Zhejiang ProvinceNational Natural Science Foundation of ChinaZhejiang Provincial Jianbing Lingyan Research and Development ProjectNational Key Research and Development Program of Chinae2406230https://www.ebi.ac.uk/biostudies/studies/S-EPMC12021085biostudies-literatureUnknown12(16)G-quadruplex (G4) structures play important roles in various biological processes, especially the gene regulation. Nucleolar protein 56 (NOP56) is an essential component in ribosome biogenesis while its overexpression associates with various types of cancers, rendering it a significant therapeutic target. Here for the first time, an antiparallel chair-type G4 structure formed by a 21-nt DNA sequence from the intron 1 of NOP56 is reported, and its high-resolution structure is determined using solution nuclear magnetic resonance spectroscopy. The NOP56-G4 has a special fold containing two G-tetrads and a C·G·C·G tetrad, which is further capped by a C∙C base pair. The G4 ligand pyridostatin (PDS) binds at the terminal G-tetrad through π-π stacking and electrostatic interactions, increasing thAdvanced science (Weinheim, Baden-Wurttemberg, Germany)Structural Insights into an Antiparallel Chair-Type G-Quadruplex From the Intron of NOP56 Oncogene.PMC12021085223741322023SDYXS000232341017QKHM25B050122225402223041762021YFA0909400Gao QJiang YLi YYan ZYang YLi CWan LWang EHe AWang YHan DGuo PfalseStructural Insights into an Antiparallel Chair-Type G-Quadruplex From the Intron of NOP56 Oncogene.G-quadruplex (G4) structures play important roles in various biological processes, especially the gene regulation. Nucleolar protein 56 (NOP56) is an essential component in ribosome biogenesis while its overexpression associates with various types of cancers, rendering it a significant therapeutic target. Here for the first time, an antiparallel chair-type G4 structure formed by a 21-nt DNA sequence from the intron 1 of NOP56 is reported, and its high-resolution structure is determined using solution nuclear magnetic resonance spectroscopy. The NOP56-G4 has a special fold containing two G-tetrads and a C·G·C·G tetrad, which is further capped by a C∙C base pair. The G4 ligand pyridostatin (PDS) binds at the terminal G-tetrad through π-π stacking and electrostatic interactions, increasing th2025-01-01T00:00:00Z2025 Apr2026-06-02T18:24:49.629Z2026-04-18T03:13:55.956ZS-EPMC120210854004722110.1002/advs.202406230