Determination of nucleic acid hydration using osmotic stress

Area of Science:

• Structural Biology
• Biophysical Chemistry
• Molecular Recognition

Background:

• Biopolymer structure and function are heavily influenced by water molecules.
• Understanding nucleic acid hydration is crucial but challenging due to its dynamic nature.
• Existing methods like X-ray crystallography and NMR offer structural insights but limited thermodynamic data on hydration.

Purpose of the Study:

• To thermodynamically analyze nucleic acid hydration using osmotic stress.
• To quantify the number of water molecules associated with double helices and released from single strands.
• To complement existing structural and dynamic data with thermodynamic contributions of water.

Main Methods:

• Utilizing osmotic stress to measure the depression of melting temperature as water activity decreases.
• Calculating the number of unique water molecules bound to nucleic acid structures.
• Comparing hydration differences across various nucleic acid sequences and modifications.

Main Results:

• Osmotic stress effectively quantifies water molecules involved in nucleic acid structure.
• The method determines the number of water molecules released during DNA melting.
• Hydration differences were observed for nucleic acids with varying sequences and modifications.

Conclusions:

• Osmotic stress provides a valuable thermodynamic approach to studying nucleic acid hydration.
• This method enhances understanding of water's role in nucleic acid conformational equilibria and recognition.
• Findings complement existing structural and dynamic data, offering a more complete picture of biopolymer hydration.