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Analyzing and Building Nucleic Acid Structures with 3DNA
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Published on: April 26, 2013

pH induced DNA folding at interface.

Hongwei Xia1, Yi Hou, To Ngai

  • 1Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China.

The Journal of Physical Chemistry. B
|December 19, 2009
PubMed
Summary
This summary is machine-generated.

Cytidine-rich DNA chains grafted to gold surfaces show pH-dependent density. Lower density DNA folds into i-motif structures, while higher density DNA exhibits limited folding due to crowding.

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Area of Science:

  • Biomaterials Science
  • Surface Chemistry
  • Molecular Biology

Background:

  • Cytidine-rich DNA sequences can form i-motif structures under acidic conditions.
  • Surface grafting of DNA is a key technique in developing biosensors and biomaterials.
  • Understanding DNA conformational changes on surfaces is crucial for controlling molecular interactions.

Purpose of the Study:

  • To investigate the effect of pH on DNA chain grafting density and conformation on a gold surface.
  • To analyze the folding behavior of DNA chains with varying grafting densities using advanced surface-sensitive techniques.
  • To determine the relationship between DNA grafting density and i-motif structure formation.

Main Methods:

  • Real-time monitoring of DNA grafting using Quartz Crystal Microbalance with Dissipation (QCM-D).
  • Surface Plasmon Resonance (SPR) to analyze DNA conformational changes.
  • Controlled manipulation of pH to induce and study DNA structural transitions.

Main Results:

  • DNA grafting density is significantly influenced by pH, with acidic conditions leading to lower density and basic conditions to higher density.
  • Lower grafting density DNA chains successfully fold into i-motif structures upon pH change.
  • Higher grafting density DNA chains show only partial folding into i-motif structures due to steric hindrance and crowding.

Conclusions:

  • Surface grafting conditions (pH) dictate DNA density and subsequent folding behavior.
  • Grafting density is a critical factor limiting the formation of higher-order DNA structures like i-motifs.
  • These findings have implications for designing DNA-based nanomaterials and surface functionalization strategies.