SYBR Green I: fluorescence properties and interaction with DNA
A I Dragan1, R Pavlovic, J B McGivney
1Institute of Fluorescence, University of Maryland Baltimore County, 701 East Pratt Street, Baltimore, MD 21202, USA.
Journal of Fluorescence
|April 27, 2012
Summary
SYBR Green I (SG) dye exhibits enhanced fluorescence upon binding to double-stranded DNA (dsDNA), attributed to restricted intramolecular motion. This dye also shows potential as a fluorescent viscosity probe due to its response to solvent viscosity.
Area of Science:
- Molecular Biology
- Biophysical Chemistry
- Spectroscopy
Background:
- SYBR Green I (SG) is a widely used fluorescent dye for detecting double-stranded DNA (dsDNA).
- Understanding the photophysical properties and binding mechanisms of SG is crucial for accurate DNA quantification and analysis.
Purpose of the Study:
- To investigate the fluorescence properties of SG and its interaction with dsDNA.
- To elucidate the mechanisms behind SG fluorescence enhancement upon DNA binding.
- To explore SG's potential as a fluorescent viscosity probe.
Main Methods:
- Fluorescence spectroscopy
- Fluorescence resonance energy transfer (FRET)
- Time-resolved fluorescence techniques
- Analysis of binding isotherms at varying ionic strengths
- Studies with DNA minor groove binders (Hoechst 33258)
Main Results:
- SG fluorescence enhancement (>1,000-fold) upon dsDNA complexation is due to the dampening of intramolecular motions.
- Multiple binding modes of SG to dsDNA were identified, including minor groove binding, intercalation, and electrostatic interactions.
- SG fluorescence and excited-state lifetime significantly increase in viscous solvents (e.g., 100% glycerol), indicating potential as a viscosity probe.
Conclusions:
- The fluorescence enhancement of SG with dsDNA is primarily linked to the restriction of its internal molecular motions.
- SG interacts with dsDNA through a combination of binding modes, contributing to its high affinity.
- SG's sensitivity to solvent viscosity suggests its utility as a novel fluorescent probe for viscosity measurements.
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