UV fluorescence of tryptophan residues effectively measures protein binding to nucleic acid fragments immobilized in gel elements of microarrays.

Microarrays allow for the simultaneous monitoring of protein interactions with different nucleic acid (NA) sequences immobilized in microarray elements. Either fluorescently labeled proteins or specific fluorescently labeled antibodies are used to study protein-NA complexes. We suggest that protein-NA interactions on microarrays can be analyzed by ultraviolet (UV) fluorescence of tryptophan residues in the studied proteins, and this approach may eliminate the protein-labeling step.