Solution structures of a G-quadruplex bound to linear- and cyclic-dinucleotides

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. Her...

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Bibliographic Details
Main Authors: Winnerdy, Fernaldo Richtia, Das, Poulomi, Heddi, Brahim, Phan, Anh Tuân
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2020
Subjects:
Online Access:https://hdl.handle.net/10356/140171
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Institution: Nanyang Technological University
Language: English
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Summary: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.