Title
Solution Structures of a G-Quadruplex Bound to Linear- and Cyclic-Dinucleotides
Author
Fernaldo Richtia Winnerdy, Poulomi Das, Brahim Heddi, Anh Tuân Phan
Year
2019
Journal
JACS
Abstract
Cyclic dinucleotides have emerged as important secondary messengers and cell signaling molecules that regulate several cell responses. A guanine-deficit G-quadruplex structure formation by a sequence containing (4n – 1) guanines, n denoting the number of G-tetrad layers, was previously reported. Here, a (4n – 1) G-quadruplex structure is shown to be capable of binding guanine-containing dinucleotides in micromolar affinity. The guanine base of the dinucleotides interacts with a vacant G-triad, forming four additional Hoogsteen hydrogen bonds to complete a G-tetrad. Solution structures of two complexes, both comprised of a (4n – 1) G-quadruplex structure, one bound to a linear dinucleotide (d(AG)) and the other to a cyclic dinucleotide (cGAMP), are solved using NMR spectroscopy. The latter suggests sufficiently strong interaction between the guanine base of the dinucleotide and the vacant G-triad, which acts as an anchor point of binding. The binding interfaces from the two solution structures provide useful information for specific ligand design. The results also infer that other guanine-containing metabolites of a similar size have the capability of binding G-quadruplexes, potentially affecting the expression of the metabolites and functionality of the bound G-quadruplexes.
Full Article
Instrument
V-650, J-815
Keywords
Absorption, G-quadruplex structure, Thermal stability, Circular dichroism, Biochemistry