RNA-Binding Peptides Inspired by the RNA Recognition Motif

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• RNA recognition motif (RRM) domains are crucial for RNA binding in proteins.
• Understanding peptide-RNA interactions is vital for contemporary biology and therapeutics.

Purpose of the Study:

• To investigate the RNA-binding capabilities of β-hairpin peptides mimicking RRM structures.
• To explore the binding affinities and selectivities of these peptides for RNA homooligonucleotides.
• To elucidate the nature of binding forces, particularly non-Coulombic interactions.

Main Methods:

• Synthesis of β-hairpin peptides with RRM-like RNA-binding sequences.
• Binding studies of peptides with RNA homooligonucleotides in aqueous solution (PBS buffer, pH 7.40).
• Analysis of binding thermodynamics and selectivity in varying salt concentrations (500 mM MgCl2).

Main Results:

• Peptides bound RNA homooligonucleotides in a 2:1 fashion with binding energies comparable to full-size RRMs (-27 to -35 kJ mol⁻¹).
• Mild selectivity was observed for binding different homooligomers.
• Binding is not predominantly driven by Coulombic attraction, as indicated by studies in high magnesium chloride concentrations.

Conclusions:

• β-hairpin peptides can effectively mimic RRM protein domains in RNA binding.
• These peptides offer a model system for studying non-Coulombic RNA-peptide interactions.
• The findings have implications for understanding prebiotic chemistry, RNA-protein evolution, and developing peptide-based therapeutics.