Various Ways to Be Negative: Biophysical Characterization of Polyanionic Biomolecules

Area of Science:

• Biochemistry
• Biophysics
• Molecular Biology

Background:

• Negatively charged biopolymers (polyanions) are essential in biological systems.
• Their diverse structures raise questions about how biophysical properties relate to function.

Purpose of the Study:

• Investigate the relationship between polyanion intrinsic features and their biophysical properties.
• Understand how these properties influence solvent organization and conformational preferences.

Main Methods:

• All-atom molecular dynamics simulations were used.
• Eleven representative polyanions (polynucleotides, polypeptides, polysaccharides) were modeled.
• Simulations were conducted in mono- and divalent counterion environments.

Main Results:

• Polyanions exhibit significant variations in compactness and flexibility.
• Conformational preferences are system-specifically modulated by cation identity (e.g., sodium, calcium).
• Each macromolecular family occupies a distinct region in conformational space.

Conclusions:

• Polyanions possess tunable biophysical properties exploitable for specific biological functions.
• Subtle differences in intrinsic features lead to unique properties even within the same family.
• The biological preference for polyanions over positively charged polymers remains an open question.