Energy-transfer photoproximity labelling in live cells using an organic cofactor

Area of Science:

• Biochemistry
• Cell Biology
• Chemical Biology

Background:

• Photocatalytic proximity labelling is crucial for studying biomolecular interactions.
• Current methods face limitations in intracellular applications due to toxicity or low resolution.

Purpose of the Study:

• To develop a biocompatible and high-resolution photocatalytic labelling method for intracellular interactome mapping.
• To characterize deazaflavin as an organic photocatalyst for diazirine activation.

Main Methods:

• Discovery and characterization of deazaflavin, an organic flavin cofactor derivative.
• Application of deazaflavin-diazirine energy-transfer labelling (DarT labelling) for cell surfaceome and intracellular interactome mapping.
• Utilizing DarT labelling to track cell-penetrating peptides and their trafficking.

Main Results:

• Deazaflavin activates diazirine via triplet energy transfer, generating carbenes with high biocompatibility.
• DarT labelling successfully mapped intracellular localization of polyarginine cell-penetrating peptides, identifying membrane interactors.
• Intracellular trafficking and exocytosis of a cyclic peptide derivative were mapped over an extended period.

Conclusions:

• DarT labelling offers a powerful, biocompatible tool for high-resolution intracellular interactome mapping.
• This method enables precise profiling of intracellular dynamics and protein interactions.
• DarT labelling has broad applicability in diverse biological systems requiring spatiotemporal control.