A novel NIR fluorescent probe for fast detection and imaging of methionine sulfoxide reductase A in lysosome of living cells

Abstract

Methionine sulfoxide reductases (Msrs) play special roles in protecting proteins from oxidative damage caused by reactive species and repairing MetSO residues in proteins/peptides. However, current probes for Msrs fail to target lysosomes and exhibit a relatively slow response and short emission wavelengths (less than 580 nm). Herein, we reported a novel lysosome-targeted NIR fluorescent probe RBSO for fast detection and imaging Msr A by extending the linear π-conjugated system of the probe via the S_NAr^H reaction. As expected, RBSO exhibited high selectivity and high sensitivity for the rapid detection of Msr A in real-time via a specific Msr A-triggered methylsulfinyl reduction reaction. Importantly, RBSO was cell-membrane permeable and capable of specifically distributing in lysosomes, and thus detects Msr A in real-time there, providing a potential tool for monitoring Msr A activity in lysosomes of living cells.