DNA hybridization kinetics: zippering, internal displacement and sequence dependence

Area of Science:

• Molecular Biology
• Biophysics
• Computational Chemistry

Background:

• Thermodynamics of DNA hybridization is well-established.
• Kinetics of DNA hybridization is less understood, yet critical for DNA nanotechnology.
• Binding rates are essential for the precise control required in DNA nanotechnology applications.

Purpose of the Study:

• To explore the kinetics of DNA oligomer hybridization.
• To elucidate the mechanisms governing DNA strand association rates.
• To understand how sequence composition influences hybridization kinetics.

Main Methods:

• Utilized a coarse-grained computational model to simulate DNA hybridization.
• Analyzed intermediate states and transition pathways during strand association.
• Investigated the role of base-pairing stability and nucleation in binding kinetics.

Main Results:

• DNA strand association involves metastable base-pairing followed by zippering.
• Initial contacts require stabilization by multiple base pairs to prevent dissociation.
• Observed non-Arrhenius behavior due to temperature-dependent nucleation.
• Identified pseudoknot and inchworm internal displacement pathways that accelerate hybridization.
• GC-rich oligomers exhibit higher association rates than AT-rich equivalents.

Conclusions:

• DNA hybridization kinetics are complex, influenced by nucleation and zippering dynamics.
• Negative effective activation enthalpies are observed due to favorable nucleation conditions.
• Alternative rearrangement pathways enhance hybridization efficiency.
• Sequence-dependent modulation of association rates is demonstrated, explaining GC-rich vs. AT-rich differences.