1. Decreased water activity in nanoconfinement contributes to the folding of G-quadruplex and i-motif structures
- Author
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Kumi Hidaka, Hiroshi Sugiyama, Prakash Shrestha, Sagun Jonchhe, Tomoko Emura, Masayuki Endo, Hanbin Mao, Shankar Pandey, and Mohammad Akter Hossain
- Subjects
Nanostructure ,Water activity ,02 engineering and technology ,Polyethylene glycol ,010402 general chemistry ,G-quadruplex ,01 natural sciences ,Polyethylene Glycols ,chemistry.chemical_compound ,Nanocages ,PEG ratio ,Molecule ,Nucleotide Motifs ,Multidisciplinary ,Water ,DNA ,Biological Sciences ,021001 nanoscience & nanotechnology ,Transition state ,0104 chemical sciences ,Nanostructures ,G-Quadruplexes ,Crystallography ,chemistry ,Models, Chemical ,0210 nano-technology - Abstract
Due to the small size of a nanoconfinement, the property of water contained inside is rather challenging to probe. Herein, we measured the amount of water molecules released during the folding of individual G-quadruplex and i-motif structures, from which water activities are estimated in the DNA nanocages prepared by 5 × 5 to 7 × 7 helix bundles (cross-sections, 9 × 9 to 15 × 15 nm). We found water activities decrease with reducing cage size. In the 9 × 9-nm cage, water activity was reduced beyond the reach of regular cosolutes such as polyethylene glycol (PEG). With this set of nanocages, we were able to retrieve the change in water molecules throughout the folding trajectory of G-quadruplex or i-motif. We found that water molecules absorbed from the unfolded to the transition states are much fewer than those lost from the transition to the folded states. The overall loss of water therefore drives the folding of G-quadruplex or i-motif in nanocages with reduced water activities.
- Published
- 2018