title: Effective rotational correlation times of proteins from NMR relaxation interference.
abstract: Knowledge of the effective rotational correlation times, tauc, for the modulation of anisotropic spin-spin interactions in macromolecules subject to Brownian motion in solution is of key interest for the practice of NMR spectroscopy in structural biology. The value of tauc enables an estimate of the NMR spin relaxation rates, and indicates possible aggregation of the macromolecular species. This paper reports a novel NMR pulse scheme, [15N,1H]-TRACT, which is based on transverse relaxation-optimized spectroscopy and permits to determine tauc for 15N-1H bonds without interference from dipole-dipole coupling of the amide proton with remote protons. [15N,1H]-TRACT is highly efficient since only a series of one-dimensional NMR spectra need to be recorded. Its use is suggested for a quick estimate of the rotational correlation time, to monitor sample quality and to determine optimal parameters for complex multidimensional NMR experiments. Practical applications are illustrated with the 110 kDa 7,8-dihydroneopterin aldolase from Staphylococcus aureus, the uniformly 15N-labeled Escherichia coli outer membrane protein X (OmpX) in 60 kDa mixed OmpX/DHPC micelles with approximately 90 molecules of unlabeled 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC), and the 16 kDa pheromone-binding protein from Bombyx mori, which cover a wide range of correlation times.
authors.affiliation: Institut für Molekularbiologie und Biophysik, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland.
authors.forename: Donghan
authors.initials: D
authors.lastname: Lee
authors.forename: Christian
authors.initials: C
authors.lastname: Hilty
authors.forename: Gerhard
authors.initials: G
authors.lastname: Wider
authors.forename: Kurt
authors.initials: K
authors.lastname: Wüthrich
mesh_terms: D000446:Aldehyde-Lyases / Q000737:chemistry*; D016880:Anisotropy; D029968:Escherichia coli Proteins / Q000737:chemistry*; D009587:Nitrogen Isotopes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D013211:Staphylococcus aureus / Q000201:enzymology
chemical_list: D029968:Escherichia coli Proteins; D009587:Nitrogen Isotopes; D000446:Aldehyde-Lyases; C020044:dihydroneopterin aldolase