title: Nitrogen-detected TROSY yields comparable sensitivity to proton-detected TROSY for non-deuterated, large proteins under physiological salt conditions.
abstract: Direct detection of the TROSY component of proton-attached (15)N nuclei ((15)N-detected TROSY) yields high quality spectra with high field magnets, by taking advantage of the slow (15)N transverse relaxation. The slow transverse relaxation and narrow line width of the (15)N-detected TROSY resonances are expected to compensate for the inherently low (15)N sensitivity. However, the sensitivity of (15)N-detected TROSY in a previous report was one-order of magnitude lower than in the conventional (1)H-detected version. This could be due to the fact that the previous experiments were performed at low salt (0-50 mM), which is advantageous for (1)H-detected experiments. Here, we show that the sensitivity gap between (15)N and (1)H becomes marginal for a non-deuterated, large protein (τ c = 35 ns) at a physiological salt concentration (200 mM). This effect is due to the high salt tolerance of the (15)N-detected TROSY. Together with the previously reported benefits of the (15)N-detected TROSY, our results provide further support for the significance of this experiment for structural studies of macromolecules when using high field magnets near and above 1 GHz.
authors.affiliation: Molecular Profiling Research Center for Drug Discovery, National Institute for Advanced Industrial Science and Technology, Tokyo, 135-0063, Japan.|PRESTO, JST, Tokyo, 135-0063, Japan.
authors.forename: Koh
authors.initials: K
authors.lastname: Takeuchi
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA, 02115, USA.
authors.forename: Haribabu
authors.initials: H
authors.lastname: Arthanari
authors.affiliation: Research and Development Department, Japan Biological Informatics Consortium, Tokyo, 135-0063, Japan.
authors.forename: Misaki
authors.initials: M
authors.lastname: Imai
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA, 02115, USA. gerhard_wagner@hms.harvard.edu.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Wagner
authors.affiliation: Molecular Profiling Research Center for Drug Discovery, National Institute for Advanced Industrial Science and Technology, Tokyo, 135-0063, Japan. shimada@iw-nmr.f.u-tokyo.ac.jp.|Graduate Schools of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan. shimada@iw-nmr.f.u-tokyo.ac.jp.
authors.forename: Ichio
authors.initials: I
authors.lastname: Shimada
mesh_terms: D002352:Carrier Proteins / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011498:Protein Precursors / Q000737:chemistry*; D011522:Protons
chemical_list: D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D011498:Protein Precursors; D011522:Protons; C059025:preMBP protein, E coli; D009584:Nitrogen
keywords: High field magnet; Nitrogen detection; Protein NMR; Salt concentration; Sensitivity; TROSY