Fig. 1

Establishment of SuperNova Green from SuperNova Red. a Protein solution of SuperNova Red (SNR) and SuperNova Green (SNG). b Sequence of SNG compared to its predecessors: KillerRed, SNR and mKillerOrange. SNG has tryptophan-based chromophore as seen in mKillerOrange and an additional Val44Ala mutation (green box). c Absorption spectra of SNR, mKillerOrange and SNG. SNG has absorbance peak at 437 nm and small shoulder at 510 nm. d Double excitation and emission spectrum of SNG. Excitation at 440 nm resulted in 510 nm emission (green solid and dashed lines respectively); excitation at 480 nm resulted in 560 nm emission (grey solid and dashed lines respectively)