Development of a Ratiometric Fluorescent Probe with Two ­Reactive Sulfoxides for Monitoring the Activity of Methionine Sulfoxide Reductase A

Abstract

Biological oxidation of methionine side chains in proteins is a process that affects the functions of many proteins. One of the key regulators of this signaling is the enzyme methionine sulfoxide reductase A (MsrA). MsrA is implicated in a number of diseases, but detailed understanding of its function is hindered by the lack of tools for monitoring the enzyme’s activity. We have designed and synthesized a probe named (S,S)-Sulfox-2 that is based on a BODIPY fluorophore and is equipped with two chiral sulfoxide units of defined stereochemistry. (S,S)-Sulfox-2 is shown to be highly responsive to MsrA and allows tracing of the MsrA activity by a significant change in the fluorescence profile.