An off-on fluorescent probe for the detection of mitochondria-specific protein persulfidation.

Protein persulfidation is a newly defined oxidative posttranslational modification and plays important roles in many biological processes. Detection of protein persulfidation in living systems is urgently needed to advance the study of H2S/H2Sn-based signalling and cellular redox regulation. Here, we developed a novel off-on fluorescent probe for the detection of persulfidation using a chemical sensor, HQO-SSH, in biological systems. HQO-SSH features fast reaction, good selectivity and high sensitivity. Due to the distinctive features of HQO-SSH, this probe was successfully applied to image protein persulfidation changes in pulmonary cells. We also demonstrated that the probe is suitable for imaging protein persulfidation in lung tissues. In addition, confocal imaging with this method revealed that sulfur mustard, a commonly used chemical warfare agent, decreased mitochondrial protein persulfidation in living lung cells and tissues. Due to these results, this probe holds great promise for exploring the role of protein persulfidation in a variety of pathophysiological conditions.