Novel peroxiredoxin-based sensor for sensitive detection of hydrogen peroxide.

A series of genetically encoded sensors have been developed to detect the important signaling molecule HO in living cells. However, more responsive and sensitive biosensors need to be developed. To address these demands, we used E. coli as a platform to develop a novel fluorescent HO sensor, which we refer to as TScGP. This sensor employs a circularly permuted YFP (cpYFP) and is based on a redox relay between peroxiredoxin (Prx) and thioredoxin (Trx). Structurally, cpYFP is sandwiched between a fungal PrxA and a C-terminal cysteine mutated TrxA that can form a stabilized disulfide bond between PrxA and TrxA in response to HO. We confirmed that TScGP can be used for detecting exogenous HO in the range of 0.5-5 μM with high selectivity and rapidly detecting HO within 30 s in E. coli. To demonstrate an application, cellular HO production by menadione was detected directly by TScGP. Our results demonstrated that using Prx-Trx combination as a sensing moiety is another strategy in designing HO sensor with high performance.