Rapid GSH detection and versatile peptide/protein labelling to track cell penetration using coumarin-based probes
Xue Li, Dehao Yu, Jing Sun, Liangyu Guan, Cheng‐Zhi Xie, Luo Wang, Yuanyuan Jia, Junyu Tian, Heli Fan, Huabing Sun
Abstract
(zebrafish embryos). Taking advantage of the fast Michael addition between the maleimide moiety and the sulfhydryl group, we expand the application of our method for fluorescent labelling of peptides/proteins and for tracking their cellular uptake process. The labelling strategy works for both Cys-bearing and Cys-free proteins after the introduction of a sulfhydryl group using Traut's reagent. Fluorescence assay reveals that the TAT-peptide can efficiently enter cells, but H3 protein, part of nucleosomes, prefers to bind on the cell membrane by electrostatic interactions, shedding light on the cellular uptake activity of nucleosomes and affording a potential membrane staining strategy. Overall, our study illustrates the broad potential of coumarin-maleimide based dual-functional probes for GSH detection and versatile protein labelling in biochemical research.