Very Fast Two-Dimensional NMR Spectroscopy for Real-Time Investigation of Dynamic Events in Proteins on the Time Scale of Seconds

摘要

One-dimensional NMR has proven in the past to be a powerful method for real-time experimental investigations of slow dynamic processes in chemistry and biochemistry such as reaction kinetics,conformational interconversion,and protein folding.However,because of its intrinsically low spectral resolution,1D NMR yields only very limited atomic resolution when applied to macromol-ecules.On the other hand,recording a series of 2D spectra,which provides the high spectral resolution,is time-demanding because each spectrum requires at least several minutes of data acquisition.Line shape analysis of cross-peaks in the indirect dimension provides information on the dynamic events occurring during 2D data acquisition,but the quality of the spectra is reduced by line broadening and line distortions,thus limiting the reliability of such an analysis.Therefore,there is a strong interest in developing fast 2D NMR techniques,where the dynamic information is encoded in the peak intensities and positions,to follow dynamic processes in proteins on a per-residue basis with a time resolution of a few seconds.Recently,Frydman and co-workers introduced "single-scan" NMR Spectroscopy,which in an ingenious way allows acquiring any multidimensional data set within a single scan.Unfortunately,the applicability of single-scan NMR to protein samples is currently limited by its inherently low sensitivity and demanding spectrometer hardware requirements.Here we present an attractive alternative for the recording of 2D ~1H-~(15)N (or ~1H- ~(13)C) correlation spectra of proteins within only a few seconds of data acquisition.The new band-Selective Optimized Flip-Angle Short-Transient heteronuclear multiple quantum coherence (SO-FAST-HMQC) experiment relies on standard data sampling in the indirect dimension and is easily implemented on any commercial NMR spectrometer.The experiment yields significantly increased sensitivity for short acquisition times when compared to other existing techniques.