5LQG

A two-quartet G-quadruplex formed by human telomere in KCl solution at neutral pH

Summary for 5LQG

• Entry DOI: 10.2210/pdb5lqg/pdb
• NMR Information: BMRB: 34034
• Descriptor: DNA (5'-D(*TP*AP*GP*GP*GP*TP*TP*AP*GP*GP*GP*TP*TP*AP*GP*GP*GP*TP*TP*AP*GP*G)-3') (1 entity in total)
• Functional Keywords: human telomere repeat, g-quadruplex, topology, dna
• Biological source: Homo sapiens (HUMAN)
• Total number of polymer chains: 1
• Total formula weight: 6958.48

Authors

Galer, P.,Wang, B.,Sket, P.,Plavec, J. (deposition date: 2016-08-17, release date: 2018-06-13, Last modification date: 2024-05-15)

Primary citation

Galer, P.,Wang, B.,Sket, P.,Plavec, J.
Reversible pH Switch of Two-Quartet G-Quadruplexes Formed by Human Telomere.
Angew.Chem.Int.Ed.Engl., 55:1993-1997, 2016

PubMed Abstract: A four-repeat human telomere DNA sequence without the 3'-end guanine, d[TAGGG(TTAGGG)2 TTAGG] (htel1-ΔG23) has been found to adopt two distinct two G-quartet antiparallel basket-type G-quadruplexes, TD and KDH(+) in presence of KCl. NMR, CD, and UV spectroscopy have demonstrated that topology of KDH(+) form is distinctive with unique protonated T18⋅A20(+) ⋅G5 base triple and other capping structural elements that provide novel insight into structural polymorphism and heterogeneity of G-quadruplexes in general. Specific stacking interactions amongst two G-quartets flanking base triples and base pairs in TD and KDH(+) forms are reflected in 10 K higher thermal stability of KDH(+) . Populations of TD and KDH(+) forms are controlled by pH. The (de)protonation of A20 is the key for pH driven structural transformation of htel1-ΔG23. Reversibility offers possibilities for its utilization as a conformational switch within different compartments of living cell enabling specific ligand and protein interactions.

PubMed: 26836334
DOI: 10.1002/anie.201507569

Experimental method

SOLUTION NMR