Optimization of Cryptic Leads from Trace Fluorescent Labeling Screening

We use trace fluorescent labeling (TFL) as a means of rapidly identifying crystals in the screening plate. The method involves the covalent labeling of between 0.1 to 0.2 % of the protein molecules with a fluorescent probe. Our standard labeling process uses the amine reactive dye 5(6)-carboxyrhodamine 6G succinimidyl ester (Invitrogen, C-6157), with reaction conditions (pH) adjusted to label random side chain amines. Previous results had shown...