Abstract:

Simultaneous data acquisition in time-sharing (TS) multi-dimensional NMR experiments has been shown an effective means to reduce experimental time, and thus to accelerate structure determination of proteins. This has been accomplished by spin evolution time-sharing of the X and Y heteronuclei, such as ¹⁵N and ¹³C, in one of the time dimensions. In this work, we report a new 3D TS experiment, which allows simultaneous ¹³C and ¹⁵N spin labeling coherence in both t₁ and t₂ dimensions to give four NOESY spectra in a single 3D experiment. These spectra represent total NOE correlations between ¹H_N and ¹H_C resonances. This strategy of double time-sharing (2TS) results in an overall four-fold reduction in experimental time compared with its conventional counterpart. This 3D 2TS CN-CN-H HSQC-NOESY-HSQC pulse sequence also demonstrates improvements in water suppression, ¹⁵N spectral resolution and sensitivity, which were developed based on 2D TS CN-H HSQC and 3D TS H-CN-H NOESY-HSQC experiments. Combining the 3D TS and the 3D 2TS NOESY experiments, NOE assignment ambiguities and errors are considerably reduced. These results will be useful for rapid protein structure determination to complement the effort of discerning the functions of diverse genomic proteins.

Keywords: HSQC; NOESY; protein NMR; proteomics; simultaneous data acquisition; time-sharing

Language: English

Document Type: Research article

Affiliations: 1: Department of Chemistry, University of Houston, Houston, TX 77004-5003, U.S.A. 2: Ontario Cancer Institute and Department of Medical Biophysics, The University of Toronto, Toronto, ON, Canada M5G 2M9 3: Ontario Cancer Institute and Department of Medical Biophysics, The University of Toronto, Toronto, ON, Canada M5G 2M9 4: Northeast Structural Genomics Consortium 5: E-mail: xgao@mail.uh.edu