Comparison List


Dreiklang is a photoswitchable green/yellow fluorescent protein published in 2011, derived from Aequorea victoria. It has high acid sensitivity.
Oligomerization Organism Molecular Weight Cofactor
Monomer Aequorea victoria 26.9 kDa -

FPbase ID: JY7XC


State Ex λ Em λ EC (M-1 cm-1) QY Brightness pKa Maturation (min) Lifetime (ns)
On 511 529 83,000 0.41 34.03 7.2 120.0  


From To Switch λ
Off On 365
On Off 405


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Dreiklang Sequence

Dreiklang was derived from Citrine with the following mutations: V61L/F64I/Y145H/N146D
amino acid numbers relative to avGFP. show relative to Citrine



Deposited: ,


We found that the fluorescence of the yellow fluorescent protein Citrine, a derivative of GFP, can be reversibly modulated to a small extent by alternate irradiation with light of 365 nm (on switching) and 405 nm (off switching), whereas fluorescence is excited at 515 nm. However, the achievable contrast was low, especially at pH values >6, rendering the reversible switching of Citrine unusable... To further develop this unusual switching behavior, we performed extensive random mutagenesis as well as directed PCR-mediated mutagenesis. In several consecutive screening rounds ∼70,000 individual clones were analyzed. Finally, we identified a mutant differing from Citrine at four positions (Citrine-V61L, F64I, Y145H, N146D), which can be effectively switched and excited to fluoresce.

Brakemann et al. (2011)

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