Abstract
Experiments detecting low gyromagnetic nuclei have recently been proposed to utilize the relatively slow relaxation properties of these nuclei in comparison to 1H. Here we present a new type of 15N direct-detection experiment. Like the previously proposed CaN experiment (Takeuchi et al. in J Biomol NMR 47:271–282, 2010), the hCaN experiment described here sequentially connects amide 15N resonances, but utilizes the initial high polarization and the faster recovery of the 1H nucleus to shorten the recycling delay. This allows recording 2D 15N-detected NMR experiments on proteins within a few hours, while still obtaining superior resolution for 13C and 15N, establishing sequential assignments through prolines, and at conditions where amide protons exchange rapidly. The experiments are demonstrated on various biomolecules, including the small globular protein GB1, the 22 kDa HEAT2 domain of eIF4G, and an unstructured polypeptide fragment of NFAT1, which contains many SerPro sequence repeats.
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Acknowledgments
This research was supported by the NIH grants GM047467, AI037581 and CA127990. Maayan Gal would like to thank the Human Frontier science Program (HFSP) for a postdoctoral fellowship. The authors would like to thank Dr. Gregory Heffron for fruitful discussions and technical assistance with the 15N direct detection setup.
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Katherine A. Edmonds and Alexander G. Milbradt have contributed equally.
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Gal, M., Edmonds, K.A., Milbradt, A.G. et al. Speeding up direct 15N detection: hCaN 2D NMR experiment. J Biomol NMR 51, 497–504 (2011). https://doi.org/10.1007/s10858-011-9580-7
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DOI: https://doi.org/10.1007/s10858-011-9580-7