mCherry is a very popular red fluorescent protein. However it has several disadvantages:
- It is shifted towards far red (ex peak 585 nm) so it often is not imaged optimally with the illumination sources and filters commonly available.
- It bleaches fast
mCherry has now been evolved into mCherry-XL with several improvements:
- This variant is shifted back towards green (ex peak 560 nm) therefore being very well excited with popular 561nm lasers.
- It is 3 times brighter than mCherry
- There is also a clear improvement in the lifetime for FLIM
- Together the 2 points above means that less excitation power is required so it should help with the bleaching problem
Here is the paper. Therefore you should consider mCherry-XL for your future tagging with red fluorescence proteins.