DNA binding fluorescent proteins for the direct visualization of large DNA molecules

Area of Science:

• Molecular Biology
• Biochemistry
• Biophysics

Background:

• Fluorescent proteins are valuable tools for biological research, aiding in cellular localization and tracking.
• Existing methods for DNA labeling can sometimes damage DNA or affect its structure.

Purpose of the Study:

• To design and characterize a novel fluorescent protein capable of binding and labeling entire DNA molecules.
• To develop a tool for optical localization and tracking of DNA with minimal perturbation.

Main Methods:

• Engineered a fluorescent protein by linking it to two peptides (KWKWKKA).
• Utilized lysine for phosphate binding and tryptophan for base intercalation for sequence-independent DNA binding.
• Investigated binding affinity (Kd) and reversibility via pH shifts.

Main Results:

• The novel fluorescent protein (FP-DBP) achieves confluent staining of DNA molecules.
• Binding is sequence-independent and reversible with pH changes.
• Demonstrated successful staining of naked DNA in microfluidics and DNA within live bacterial cells.

Conclusions:

• The developed FP-DBP is a robust tool for single DNA molecule studies.
• It offers advantages such as lack of photocleavage and preservation of DNA polymer contour length.
• This technology has broad applications in molecular biology and diagnostics.