RTACQ4PSNMR · Ultrahigh resolution NMR tools for chemistry and structural biology

Solution NMR spectroscopy is among the most important techniques in natural science, particularly for structural biology and organic chemistry research. Spectral resolution and sensitivity are the key parameters controlling access to structural information at the atomic level; at present it is resolution that limits the complexity of structural problem, whether chemical or biological, that NMR can be applied to. Multidimensional NMR has allowed huge strides to be made in studies of the 3D structure and dynamics of complex molecules, but in each dimension the multiplet structure caused by homonuclear couplings sets the resolution limit. Very recently, an improvement to one of the most widely-used and prototypical techniques, the HSQC experiment, has been published by the NMR methodology group at Manchester University headed by Gareth Morris and Mathias Nilsson. This uses for the first time suppression of homonuclear proton-proton couplings in real time during HSQC data acquisition, and results in a simultaneous improvement of a factor of two or more in both resolution and sensitivity, marking a significant breakthrough. Initial results confirm that the basic approach is viable in macromolecular systems, including proteins. Similar approaches should be applicable to a wide range of multidimensional techniques, and have the potential to increase significantly the structure-determining power of NMR. This project sets out plans for the development of a range of novel real-time acquisition methods, including for example improved 3D triple-resonance pulse sequences for protein backbone assignment, and exploiting synergies between real-time homonuclear decoupling and non-uniform data sampling methods to maximise the efficiency of structural studies of complex systems by NMR.