Figure 2

Photoactivation of fluorescent proteins at 294 K and 77 K. (a) Photoactivation of fluorescent proteins at 294 K. Fluorescent probes were activated with a 2.5 sec. 405 nm laser pulse every 20 sec, and fluorescence was monitored using excitation at 488 nm. (b) Identical photoactivation as shown in a, but at 77 K of vitrified fluorescent proteins on EM grids.