Excitation and Emission Wavelengths of Common Fluorescent Proteins

Fluorescent proteins are widely used as reporters, fusion tags, and imaging tools in molecular and cell biology. Selecting the appropriate fluorescent protein requires consideration of its excitation and emission wavelengths, brightness, oligomeric state, and other optical properties.

The table below summarizes the key properties of commonly used fluorescent proteins, including their excitation wavelength, emission wavelength, molar extinction coefficient, quantum yield, oligomeric state, and relative brightness compared with EGFP.

How to Choose a Fluorescent Protein

When selecting a fluorescent protein for an experiment, consider the following factors:

• Excitation and emission wavelengths: Choose a fluorescent protein that matches the excitation source and detection channels of your microscope, flow cytometer, or other imaging system.

• Brightness: Fluorescence brightness is influenced by both the molar extinction coefficient and quantum yield. Brighter fluorescent proteins can be advantageous when expression levels are low or imaging conditions are challenging.

• Oligomeric state: Monomeric fluorescent proteins are generally preferred for fusion constructs because oligomerization can interfere with the localization or function of the target protein.

• Photostability: For long-term live-cell imaging or repeated imaging, fluorescent proteins with higher photostability may be preferable.

• Spectral separation: When performing multicolor imaging, select fluorescent proteins with sufficiently separated excitation and emission spectra to minimize spectral overlap and bleed-through.

Choosing the right fluorescent protein based on the experimental system and imaging platform can improve signal quality and facilitate accurate detection of protein localization, expression, and cellular dynamics.