A rapidly maturing far-red derivative of DsRed-Express2 for whole-cell labeling
Authors: Strack RL, Hein B, Bhattacharyya D, Hell SW, Keenan RJ, Glick BS
CellNetworks People: Hell Stefan
Journal: Biochemistry. 2009 Sep 8;48(35):8279-81. doi: 10.1021/bi900870u

Fluorescent proteins (FPs) with far-red excitation and emission are desirable for multicolor labeling and live-animal imaging. We describe E2-Crimson, a far-red derivative of the tetrameric FP DsRed-Express2. Unlike other far-red FPs, E2-Crimson is noncytotoxic in bacterial and mammalian cells. E2-Crimson is brighter than other far-red FPs and matures substantially faster than other red and far-red FPs. Approximately 40% of the E2-Crimson fluorescence signal is remarkably photostable. With an excitation maximum at 611 nm, E2-Crimson is the first FP that is efficiently excited with standard far-red lasers. We show that E2-Crimson has unique applications for flow cytometry and stimulated emission depletion (STED) microscopy.