A Genetically Encoded β‐Lactamase Reporter for Ultrasensitive 129Xe NMR in Mammalian Cells |
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| Authors: | Yanfei Wang Benjamin W Roose Eugene J Palovcak Dr Vincenzo Carnevale Prof Ivan J Dmochowski |
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| Affiliation: | 1. Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA;2. Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, PA, USA |
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| Abstract: | Molecular imaging holds considerable promise for elucidating biological processes in normal physiology as well as disease states, but requires noninvasive methods for identifying analytes at sub‐micromolar concentrations. Particularly useful are genetically encoded, single‐protein reporters that harness the power of molecular biology to visualize specific molecular processes, but such reporters have been conspicuously lacking for in vivo magnetic resonance imaging (MRI). Herein, we report TEM‐1 β‐lactamase (bla) as a single‐protein reporter for hyperpolarized (HP) 129Xe NMR, with significant saturation contrast at 0.1 μm . Xenon chemical exchange saturation transfer (CEST) interactions with the primary allosteric site in bla give rise to a unique saturation peak at 255 ppm, well removed (≈60 ppm downfield) from the 129Xe‐H2O peak. Useful saturation contrast was also observed for bla expressed in bacterial cells and mammalian cells. |
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| Keywords: | contrast agents molecular imaging NMR reporter genes protein biophysics supramolecular chemistry |
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