Structural Differences at Quadruplex-Duplex Interfaces Enable Ligand-Induced Topological Transitions.

ABSTRACT: Quadruplex-duplex (QD) junctions, which represent unique structural motifs of both biological and technological significance, have been shown to constitute high-affinity binding sites for various ligands. A QD hybrid construct based on a human telomeric sequence, which harbors a duplex stem-loop in place of a short lateral loop, is structurally characterized by NMR. It folds into two major species with a (3+1) hybrid and a chair-type (2+2) antiparallel quadruplex domain coexisting in a K⁺ buffer solution. The antiparallel species is stabilized by an unusual capping structure involving a thymine and protonated adenine base AH⁺ of the lateral loop facing the hairpin duplex to form a T·AH⁺·G·C quartet with the interfacial G·C base pair at neutral pH. Addition

SUBMITTER: Vianney YM 

PROVIDER: S-EPMC11200018 | biostudies-literature | 2024 Jun

REPOSITORIES: biostudies-literature