Atto550-LPETGG is the sortase sequence, LPETGG, coupled to the fluorescent label Atto550. Atto550-LPETGG can be used for site-specific labeling of target proteins using sortase-catalyzed transpeptidation. In this process, sortase A cleaves between the thr and gly residues, forming a thioester intermediate with the peptide probe. A protein N-terminally engineered with a series of glycine residues resolves this intermediate, regenerating the active site cysteine of sortase and conjugating the probe to the N-terminus of the protein. Atto550-LPETGG contains the Atto550 fluorescent label which is efficiently excited in the range 540 - 565 nm, with strong absorption, high fluorescence quantum yield and high photo-stability.
