A Highly Responsive and Selective Fluorescent Probe for Imaging Physiological Hydrogen Sulfide

The discovery of hydrogen sulfide (H₂S) as a novel gasotransmitter for cell signaling and other pathophysiological processes has spurred tremendous interest in developing analytical methods for its detection in biological systems. Herein, we report the development of a highly responsive and selective genetically encoded H₂S probe, hsGFP, for the detection of H₂S both <i>in vitro</i> and in living mammalian cells. hsGFP bestows a combination of favorable properties, including large fluorescence responses, high efficiency in folding and chromophore formation, and excellent sensitivity and selectivity toward H₂S. As a genetically encoded probe, hsGFP can be readily and precisely localized to subcellular domains such as mitochondria, cell nuclei, and ion channels. hsGFP was further utilized to image H₂S enzymatically produced from l-cysteine in human embryonic kidney (HEK) 293T cells