Figure 1.

(a) Absorption (solid line), fluorescence excitation (dotted line), and emission (dashed line) spectra of eqFP611. For the excitation spectrum, the emission was measured at 611 nm; for the emission spectrum, fluorophores were excited at 546 nm. (Inset) Exponential fluorescence decay with a lifetime of 2.5 ns. (b) pH dependence of eqFP611 fluorescence emission at 611 nm upon excitation at 559 nm. (c) Maturation of eqFP611 and drFP583 (DsRed) at 24.5°C. eqFP611 red fluorescence maturation (closed spheres) proceeds by means of a green fluorescent intermediate (open spheres) and is essentially complete after 12 h and thus significantly faster than DsRed maturation (squares).