Atto 550 (Figure 1) is related to Rhodamine 6G, and it consists of 3 isomers bearing identical absorbance and fluorescence. This dye presents strong absorption and high quantum yield, which is referred as the ratio between absorbed photons and emitted fluorescence photons. It is usually coupled to DNA and RNA oligonucleotides and it has a good photo-stability. Atto 550 can be used as an alternative of Alexa Fluor®546, 555.
Figure 1. Structure of 5'-Atto 550 (R = sequence).
metabion offers the Atto 550 modification in its DNA and RNA portfolio: