a.k.a. DsRed.T1, T1
|Tetramer||Discosoma sp.||25.7 kDa||-|
|Ex λ||Em λ||EC (M-1 cm-1)||QY||Brightness||pKa||Maturation (min)||Lifetime (ns)|
|t1/2 (s)||Power||Light||Mode||In Cell||Fusion||˚C||Reference|
|71.0||Shaner et al. (2004)|
DsRed-Express was derived from DsRed with the following mutations: R2A/K5E/N6D/T21S/H41T/N42Q/V44A/C117S/T217A
DsRed.T1 is essentially identical to DsRed.T4, except that DsRed.T1 lacks cysteine residues and therefore might fold more efficiently in the oxidizing environment of the secretory pathway.
To overcome the slow maturation of DsRed, we used random and directed mutagenesis to create variants that mature 10–15 times faster than the wild-type protein. An asparagine-to-glutamine substitution at position 42 greatly accelerates the maturation of DsRed, but also increases the level of green emission. Additional amino acid substitutions suppress this green emission while further accelerating the maturation.