SYBR Gold is an asymmetrical Cyanine. It can be used as a stain for DNA, DNA, and RNA. SYBR Gold is the most sensitive Fluorophore of the SYBR family of dyes for the detection of Nucleic acid. The SYBR family of dyes is produced by Molecular Probes, now owned by Thermo Fisher Scientific
SYBR Gold is more sensitive than ethidium bromide, SYBR Green I, and SYBR Green II for detecting various types of Nucleic acid. SYBR Gold's superior sensitivity is due to the high fluorescence quantum yield of the dye-nucleic acid complexes (~0.6-0.7) and the dye's large fluorescence enhancement upon binding to Nucleic acid (~1000-fold). SYBR Gold can detect as little as 25 pg of DNA which makes it >10-fold more sensitive than ethidium bromide for detecting Nucleic acid in denaturing urea, Glyoxal, and formaldehyde gels, even with 300 nm transillumination.
Fluorescence properties
SYBR Gold has two
fluorescence excitation maxima when bound to
DNA, one centered at ~300 nm and one at ~495 nm, and a single emission maximum at ~537 nm. SYBR Gold exhibits improved DNA cloning efficiency compared to others
Dye of the SYBR family because it can be excited with blue light transillumination, which does not cause
DNA damage.
The
fluorescence intensity increases linearly with the number of SYBR Gold molecules bound to
DNA up to dye concentrations of ~ 2.5 μM, where quenching and inner filter effects become relevant. For dye concentrations ≤ 2.5 μM the
fluorescence intensity as a function of the
DNA concentration is well described by a global binding model for
dye concentrations.
Binding to DNA
SYBR Gold is an intercalator. This means it binds to
DNA by insertion of one
dye molecule between two planar
Nucleobase /
Base pair of
DNA. Single molecule magnetic tweezers assays reveal systematic lengthening and unwinding of
DNA by 19.1º ± 0.7º per
dye molecule upon binding, consistent with intercalation. This is similar to related
Dye like SYBR Green I. The dissociation constant – a measure to describe the
binding affinity of SYBR Gold to
DNA – is 0.27 ± 0.03 μM.
Uses
SYBR Gold is used in several areas of molecular biology and
biochemistry. Its main use is to visualise
DNA in
electrophoresis, for example agarose or polyacrylamide gels. SYBR Gold is able to penetrate thick and high percentage agarose gels rapidly, and even
formaldehyde agarose gels do not require de-staining, due to the low intrinsic
fluorescence of the unbound
dye. SYBR Gold can be readily removed from
Nucleic acid by ethanol precipitation, leaving pure templates available for subsequent manipulation or analysis.
Also, SYBR Gold can also be used for labelling of DNA within cells for flow cytometry and fluorescence microscopy.
To preserve fluorescence activity, SYBR Gold should be protected from light as much as possible, particularly once it has been diluted for use.
Safety
The SYBR family of dyes is marketed as a replacement for
ethidium bromide, a potential
Mutagen, as both safer to work with and free from the complex waste disposal issues of
Ethidium bromide. But no data are available addressing the
Mutagen or
toxicity of SYBR Gold. Because SYBR Gold binds to
DNA in an intercalative way with high affinity which makes it a possible
carcinogen. Therefore, SYBR Gold should be handled with particular caution and solutions of SYBR Gold stain should be disposed of in accordance with local regulations
Similar cyanine dyes
