An l-2-hydroxyglutarate biosensor based on specific transcriptional regulator LhgR

Abstract l -2-Hydroxyglutarate ( l- 2-HG) plays important roles in diverse physiological processes, such as carbon starvation response, tumorigenesis, and hypoxic adaptation. Despite its importance and intensively studied metabolism, regulation of l- 2-HG metabolism remains poorly understood and none of regulator specifically responded to l- 2-HG has been identified. Based on bacterial genomic neighborhood analysis of the gene encoding l -2-HG oxidase (LhgO), LhgR, which represses the transcription of lhgO in Pseudomonas putida W619, is identified in this study. LhgR is demonstrated to recognize l -2-HG as its specific effector molecule, and this allosteric transcription factor is then used as a biorecognition element to construct an l -2-HG-sensing FRET sensor. The l -2-HG sensor is able to conveniently monitor the concentrations of l -2-HG in various biological samples. In addition to bacterial l- 2-HG generation during carbon starvation, biological function of the l -2-HG dehydrogenase and hypoxia induced l- 2-HG accumulation are also revealed by using the l -2-HG sensor in human cells.