Multifunctional energy landscape for a DNA G-quadruplex: An evolved molecular switch.

Area of Science:

• Biochemistry
• Structural Biology
• Genetics

Background:

• Telomeres protect chromosome ends.
• G-quadruplexes are DNA structures found in telomeres.
• Multiple G-quadruplex topologies exist, leading to experimental discrepancies.

Purpose of the Study:

• To investigate the energy landscape of four-fold telomere repeats.
• To elucidate interconversion pathways between different G-quadruplex topologies.
• To provide a framework for understanding G-quadruplex behavior and experimental results.

Main Methods:

• Computational modeling of DNA G-quadruplex structures.
• Analysis of energy landscapes to identify stable states and transition pathways.
• Comparison of theoretical pathways with existing experimental data.

Main Results:

• A multi-funnel energy landscape was identified for the four-fold telomere repeat.
• Multiple intermediate configurations and misfolded states were revealed.
• Interconversion pathways between six experimentally characterized G-quadruplex topologies were mapped.

Conclusions:

• The complex energy landscape explains the existence of multiple G-quadruplex structures.
• This multi-funnel organization reflects the intrinsically multi-functional nature of telomeric DNA.
• A new paradigm for classifying G-quadruplexes is proposed, resolving conflicting experimental observations.