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¹⁵N TROSY CEST experiment

Files

You can get the example files from the GitHub ChemEx page.

This example demonstrates the analysis of datasets from ¹⁵N TROSY CEST experiment (cest_15n_tr). Compared with ¹⁵N pure in-phase CEST experiment (cest_15n), the TROSY version benefits from TROSY effects therefore the relaxation property is more favorable. From this experiment it is possible to measure certain parameters about excited state that are difficult to obtain from other experiments, such as solvent exchange rate.1

Note that antitrosy key should be set properly in experiment files to indicate whether the datasets are measured for TROSY or anti-TROSY component. The current example includes both TROSY and anti-TROSY datasets, while it is also possible to analyze TROSY datasets alone. Also note that ¹⁵N chemical shifts provided in parameter files should correspond to the "actual" value in the absence of ¹JHN, therefore a separate non-TROSY HSQC might be required to obtain the correct value, or an alternative strategy is to correct chemical shifts obtained from TROSY HSQC with the size of ¹JHN.

Footnotes​

  1. D. Long, G. Bouvignies, and L. E. Kay. Measuring Hydrogen Exchange Rates in Invisible Protein Excited States. Proc. Natl. Acad. Sci. USA 111, 8820-8825 (2014). https://doi.org/10.1073/pnas.1405011111 ↩