In the early 1980s, a magnificent series of developments and half a century of research culminated in the ability to reliably derive three-dimensional, atomic resolution structures of small proteins from the NMR signals of nuclear spins. However, the many hundreds or even thousands of unique 1H signals in any given protein made the analysis of their NOE interaction network a formidable task. The development of molecular cloning and bacterial overexpression came to the rescue by offering a straightforward avenue to enriching the 13C and 15N isotopic composition of proteins, thereby making it possible to access the plethora of heteronuclear NMR techniques originally developed for small organic molecules. By dispersing the interaction between 1H, 13C and 15N spins in three- or even four-dimensional NMR spectra, resonance overlap was greatly diminished, thereby tremendously simplifying spectral analysis and greatly extending the size limit of proteins amenable to NMR in subsequent decades. As an additional benefit, the relaxation properties of individual 15N and 13C spins, which are well-defined reporters for motions within their structural framework, enabled the characterization of internal protein dynamics in exquisite detail.
Currently, much of biological NMR is focused on unraveling the mechanisms behind protein function, revealing the functional importance of protein and nucleic acid dynamics and the details of pivotal transiently populated states. One area that has remained largely intractable to all biophysical methods concerns the structure and dynamics of rapidly forming oligomeric aggregates of proteins linked to amyloid disease. By exploiting the long-recognized sensitivity of such systems to hydrostatic pressure, we demonstrate that pressure-jump NMR experiments now starts to reveal atomic details of such species.