Structural precursor of the hemideprotonated guanine pair

Area of Science:

• Biochemistry
• Chemical Physics
• Molecular Biology

Background:

• Guanine nucleobases are fundamental components of nucleic acids.
• Understanding base pairing is crucial for molecular biology and genetics.
• Specific interactions involving water molecules can influence base pairing stability.

Purpose of the Study:

• To present a novel pairing scheme between two neutral guanine nucleobases.
• To investigate the role of water molecules in guanine base pairing.
• To explore the potential conversion of this neutral pair into a hemideprotonated form.

Main Methods:

• Computational modeling and simulation of guanine nucleobases.
• Analysis of hydrogen bonding networks involving water molecules.
• Investigation of proton transfer events and their energetics.

Main Results:

• A specific neutral guanine-guanine (GG7) pairing via Watson-Crick faces involving two water molecules was identified.
• The GG7 pair demonstrated stability under specific conditions.
• Removal of a hydronium ion (H5O2+) from the GG7 complex was shown to yield a hemideprotonated guanine pair (GG5).

Conclusions:

• A new water-mediated neutral guanine-guanine pairing (GG7) has been characterized.
• This pairing is potentially reversible, converting to a hemideprotonated form (GG5).
• The findings contribute to the understanding of non-canonical base pairing and the role of water in molecular recognition.