NMR-based conformational analysis of DNA G-quadruplex guides mapping essential structure-function relationship in...

Area of Science:

• Biochemistry
• Structural Biology
• Nucleic Acid Chemistry

Background:

• G-quadruplexes (G4s) are non-canonical DNA structures with emerging roles in protein chaperoning.
• Understanding the structure-function relationship of G4s is crucial for elucidating their biological roles.

Purpose of the Study:

• To determine the base-level resolution structure and topology of a G-rich DNA sequence (Seq576) with protein chaperoning activity using solution NMR.
• To investigate the G4 structural properties essential for chaperoning protein aggregation and folding through structure-function studies.

Main Methods:

• Solution Nuclear Magnetic Resonance (NMR) spectroscopy was employed to determine the structure of Seq576 without requiring chemical shift assignments.
• Site-directed mutagenesis and chaperone activity assays were performed to link structural insights to functional properties.

Main Results:

• Seq576 was found to adopt two distinct conformations on the slow exchange timescale, attributed to a G-register shift.
• Specific G4 structural features were identified as critical for effective chaperoning of protein aggregation and folding.

Conclusions:

• This study demonstrates a cost-effective and rapid NMR approach for detailed nucleic acid structural biology and functional analysis.
• The findings provide insights into G-quadruplexes as regulators of protein homeostasis and highlight potential therapeutic strategies targeting G4 structures.