Fluorescent labeling of recombinant proteins in living cells with FlAsH.

TLDR: FlAsH labeling of recombinant proteins for cellular localization studies can be considered an alternative to the popular method using green fluorescent protein (GFP) fusions, with the FlAsH method having some advantages.

Abstract: Publisher Summary FlAsH labeling of recombinant proteins for cellular localization studies can be considered an alternative to the popular method using green fluorescent protein (GFP) fusions, with the FlAsH method having some advantages. The size of the fluorescent tag is considerably smaller: bound FlAsH has a molecular weight of less than 600 and the addition of a FlAsH target site can be as small as four introduced cysteines with an appended peptide adding less than 2 kDa. This compares with a molecular weight of 30,000 for GFP, which is more likely to perturb the native structure and function of the tagged protein. Both FlAsH and GFP tagging generate a fluorescent protein with similar brightness. However, multiple FlAsH sites can be introduced into a protein so that considerably brighter labeling aid in detecting low-abundance proteins. A major advantage of the FlAsH system is the comparative ease of chemical modification of FlAsH. Coupled with the synthetic versatility of organic chemistry, this enables the incorporation of functionalities other than fluorescence into targeted proteins or peptides.