Hydration Water Drives the Self-assembly of Guanosine Monophosphate

We present the temperature-dependent terahertz (1.5-12 THz, 50-400 cm-1) absorptivity spectra of aqueous Na2GMP solution (GMP) in comparison with the aqueous solutions of other RNA nucleotides. Distinct absorption features were observed in the spectrum of GMP, which we attribute to the intramolecular modes of the self-assemblies (i.e., G-complexes) that, at 1 M, start to form at 313 K and below. Changes in broad band features of the terahertz spectrum were also observed, which we associate with the release of hydration water in the temperature-dependent formation of G-quadruplex (G4). Using a state-of-the-art THz calorimetry approach correlating spectroscopic to thermodynamic changes, we propose a molecular mechanism of hydrophilic hydration driving GMP self-assembly as a function of temperature. The free energy contribution of hydrophilic hydration is shown as a decisive factor in G4 formation. Our findings spotlight the role of hydration in the formation of macromolecular structure, and suggest the potential of hydration-tuning for regulating DNA transcription and replication.PMID:38454599 | DOI:10.1016/j.bpj.2024.03.005
Source: Biophysical Journal - Category: Physics Authors: Source Type: research