70724  FRETWorks™ S•Tag™ Assay Kit

Ultrasensitive, homogeneous, fluorescent assay of S•Tag fusion proteins

The FRETWorks™ S•Tag™ Assay is a FRET-based method that enables extremely sensitive detection of S•Tag fusion proteins in minutes with a homogeneous format. The interaction of the 15–amino acid S•Tag fusion peptide with purified S-protein reconstitutes RNase activity, which is measured using the FRET ArUAA substrate. The substrate consists of a short, mixed ribo/deoxyribooligonucleotide having a fluorophore on the 5′-end and a quencher on the 3′-end (Keleman 1999). Fluorescence of the uncleaved molecule is inhibited by the interaction of the fluorophore and quencher; upon cleavage of the intervening ribonucleotide residue, the fluorophore is released and becomes highly fluorescent. The specificity of the substrate permits this assay to be performed with crude extracts. No reagent injection is necessary, and the signal is stable for > 6 hours.

The FRETWorks S•Tag Assay Kit is compatible with the PopCulture^® Reagent (including the additives Benzonase^® Nuclease and rLysozyme™ Solution), making these reagents an ideal combination for rapid, automatable screening of protein expression.