A new twist on PIFE: photoisomerisation-related fluorescence enhancement

Abstract

PIFE was first used as an acronym for protein-induced fluorescence enhancement, which refers to the increase in fluorescence observed upon the interaction of a fluorophore, such as a cyanine, with a protein. This fluorescence enhancement is due to changes in the rate of cis/trans photoisomerisation. It is clear now that this mechanism is generally applicable to interactions with any biomolecule and, in this review, we propose that PIFE is thereby renamed according to its fundamental working principle as photoisomerisation-related fluorescence enhancement, keeping the PIFE acronym intact. We discuss the photochemistry of cyanine fluorophores, the mechanism of PIFE, its advantages and limitations, and recent approaches to turn PIFE into a quantitative assay. We provide an overview of its current applications to different biomolecules and discuss potential future uses, including the study of protein-protein interactions, protein-ligand interactions and conformational changes in biomolecules.

Plasmonic Fluorescence Sensors in Diagnosis of Infectious Diseases

“…This leads to a remarkable 70-fold increase in fluorescence intensity under optimal conditions and enables the detection of glucose in serum samples, demonstrating a low limit of detection (10 μM) and a linear response within the concentration range of 50 μM to 2000 μM. Protein-induced fluorescence enhancement is a powerful method that significantly enhances fluorescence intensity when a protein binds closely, allowing for high-resolution studies of molecular interactions without the need for protein labeling [ 222 , 223 , 224 ].…”

PEPCy: Photostable fluoromodules for live cell, super-resolution microscopy of surface proteins

“…S1E, F, Table 1). Due to the innate environmental sensitivity of cyanine dyes [20,21], we explored whether PEPCy tags modified the fluorescence lifetimes of their cognate dyes. Fluorescence lifetime microscopy (FLIM) of PEPCy expressing yeast cells showed that both PEPCy3 and PEPCy5 increased the lifetime of their cognate cyanine dyes compared to covalent targeting of the dyes via HT (Fig.…”