GFP vs. MCherry

Attribute	GFP	MCherry
Fluorescent color	Green	Red
Excitation wavelength	488 nm	587 nm
Emission wavelength	509 nm	610 nm
Protein size	238 amino acids	236 amino acids

Introduction

Green fluorescent protein (GFP) and monomeric Cherry (mCherry) are two commonly used fluorescent proteins in biological research. They are both widely utilized for labeling and tracking proteins, cells, and organelles in live cells and tissues. While both proteins share similarities in their fluorescence properties, they also have distinct attributes that make them suitable for different experimental applications.

Fluorescence Properties

One of the key similarities between GFP and MCherry is their ability to fluoresce when exposed to specific wavelengths of light. GFP emits a green fluorescence when excited by blue or UV light, while MCherry emits a red fluorescence when excited by green or yellow light. Both proteins have high quantum yields, meaning they efficiently convert absorbed light into emitted fluorescence, making them ideal for imaging applications.

Maturation Time

One important difference between GFP and MCherry is their maturation time. GFP matures quickly, reaching its full fluorescence potential within hours of synthesis. In contrast, MCherry has a longer maturation time, taking several hours to days to reach its maximum fluorescence intensity. This difference in maturation time can impact experimental design, as researchers may need to consider the timing of protein expression and imaging when choosing between GFP and MCherry.

Photostability

Another important attribute to consider when comparing GFP and MCherry is their photostability. GFP is known for its high photostability, meaning it can withstand prolonged exposure to light without losing fluorescence intensity. On the other hand, MCherry is more prone to photobleaching, especially when exposed to intense light for extended periods. Researchers working with MCherry may need to take extra precautions to minimize photobleaching during imaging experiments.

Monomeric vs. Oligomeric

GFP is a monomeric protein, meaning it exists as a single unit when expressed in cells. This monomeric nature allows GFP to be used as a fusion tag without interfering with the function of the protein of interest. In contrast, MCherry is an oligomeric protein, forming tetramers when expressed. This oligomeric structure can impact the localization and behavior of the fusion protein, potentially influencing experimental outcomes.

Color Options

While both GFP and MCherry are known for their green and red fluorescence, respectively, it is worth noting that there are variants of these proteins available in different colors. For example, GFP has been engineered to produce blue, cyan, and yellow fluorescence, expanding the color palette for labeling and imaging experiments. Similarly, MCherry variants with different emission spectra have been developed, providing researchers with additional options for multicolor imaging studies.

pH Sensitivity

One unique attribute of MCherry compared to GFP is its pH sensitivity. MCherry exhibits a pH-dependent shift in its fluorescence emission, with a decrease in pH leading to a red shift in the emission spectrum. This pH sensitivity can be advantageous for studying cellular processes that involve changes in pH, such as endocytosis and lysosomal function. GFP, on the other hand, is less pH-sensitive, making it more suitable for applications where pH changes are not a concern.

Conclusion

In conclusion, GFP and MCherry are both valuable tools for fluorescence imaging in biological research. While they share similarities in their fluorescence properties, they also have distinct attributes that make them suitable for different experimental applications. Researchers should consider factors such as maturation time, photostability, oligomeric structure, color options, and pH sensitivity when choosing between GFP and MCherry for their imaging studies.