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In the 53 years since the discovery of nuclear magnetic resonance (NMR) spectroscopy, magnetic resonance technologies have had a profound impact on a broad range of disciplines. No other branch of spectroscopy has had a greater influence on chemistry, biology, and materials science; and no other technology holds better potential for addressing the needs and opportunities of far-reaching areas of science and engineering. New developments in this technology are positioning NMR as a key research tool for critical initiatives on the national scientific agenda, such as capitalizing on results for the genome projects, targeted drug design, strategies for lowering the costs of health care, development of new materials, new approaches to control diseases and ways to protect and clean up the environment. New high magnetic field NMR instrumentation that is capable of tackling these important scientific, economic, environmental, and medical issues comes at a very high price. Its potential, nonetheless, is widely recognized and has been affirmed: approximately $500 million is being invested in a new institute housing a national NMR center near Yokohama, Japan. For the United States to meet this challenge cost effectively and to seize the imminent scientific and educational opportunities, a new approach for funding NMR instrumentation is essential. We propose the establishment of a National Magnetic Resonance Collaboratorium (NMRC)-a virtual laboratory or "center without walls" that would network collaborations among sites and the nation's biological, chemical and materials science communities creating a national resource that would integrate magnetic resonance-related science, education, and technology to levels and capabilities never before envisioned. Recent advancements in computational and connectivity power now available to the science and engineering communities would bring new dimensions to communications between research groups across disciplinary boundaries. NMRC sites, or "Sectors," would build on existing investments in faculty, instrumentation, and skilled spectroscopists at centers of NMR excellence throughout the country. Collectively, the Sectors of the NMRC would prepare the United States for the competitive challenges at hand and lay a framework from within which the United States could lead multidisciplinary magnetic resonance research and development into the 21st century. They would represent a new investment in distributed user facilities, providing nationwide remote access and linking all users and participants as partners in meeting the United States' challenges in science and education. Background Scientific Agenda Beyond the Genome. By the year 2005, 100,000 amino acid sequences representing the proteins of the human genome will be known. This is just one of several genomes currently being sequenced. Each protein performs one or more specific functions, often accomplished via complex mechanisms, and the best approach to modifying function (which could be as important for laboratory bench chemistry as for medicine) is understanding the mechanisms. Describing complex mechanisms and reaction kinetics requires a detailed knowledge of structure, dynamics, and chemical properties. Structure prediction methods based on sequence homology will lead to low resolution structural models for many of the protein sequences. It is anticipated, however, that 3,000 to 10,000 experimental structures will need to be determined to identify all of the structural families in the human proteome. The dynamic properties of individual proteins and their chemical properties (activities) will be more difficult to predict. Although NMR is playing an increasingly important role in such characterizations, the rate of NMR data collection and analysis must accelerate to meet the challenges. New instrumentation and methodology will lead to better structures and more accurate descriptions of dynamics and chemical properties of proteins; they also will extend the NMR approach to larger and more interesting proteins and nucleic acids, potentially doubling the current size limit. NMR is already the technique of choice for experimentally defining molecular dynamics. Moreover, NMR's potential to return information on proteins in diverse environments including amorphous aggregates and membrane surfaces will increase its structural role. Gene Regulation. Tremendously complicated molecular machinery is involved in gene regulation and other cellular activities. Understanding regulatory processes is key to developing methods to regain control of aberrant processes, to treat disease, and to manipulate cells for new functions in biotechnology. Biochemical activities are regulated by ligand and protein binding processes that result in changed conformation, dynamics, or stability. Macromolecular complexes consisting of RNA, DNA, and proteins constitute molecular machines. The structural and dynamic characterization of these molecular complexes is an essential part of understanding their activity and interconnectivity. While domain structures rather than intact proteins can be used in studies of complex formation, the NMR molecular weight limit for structure determination is easily exceeded when a structural picture of the whole system is desired. Higher fields, new probe technology, novel isotope labeling strategies, and data collection protocols will dramatically expand the range of molecular structure that can be approached by solution NMR. Indeed, complementary techniques of molecular biology, X-ray crystallography, and NMR spectroscopy have led, synergistically, to notable insights into mechanisms used by regulatory domains, but much more progress is needed to meet the important health, bio-engineering, and environmental science challenges of the coming millennium. Neuroscience. The human brain has 30 x 10 9 synapses that are tightly regulated. Communications across these
synapses are primarily regulated by membrane proteins. In fact,
30% of the human genome represents membrane and membrane- associated
proteins for which there is a paucity of structural and dynamic
information. Without this knowledge, we have been unable to obtain
a functional understanding of synapses at the atomic level. Membranes
form a spectacular two- dimensional array of molecular activities
that is very different from the three-dimensional world of mobile
water soluble proteins. The heterogeneity of the membrane environment,
however, has prevented routine crystallization required for X-ray
crystallography and the formation of isotropic solutions needed
for solution NMR analysis. Solid- state NMR, which has no correlation
time limit or crystallization requirement, is thus arguably the
most promising approach for high resolution structural and dynamic
characterizations of these proteins. A recent high resolution
polypeptide structure in a lipid environment and recent spectra
of uniformly labeled membrane proteins clearly demonstrate this
potential for solid-state NMR. Other heterogeneous structures
such as The prospects of greatly improved sensitivity and resolution discussed above are critical for the continued advances in solid-state NMR investigations of the structure and dynamics of macromolecules in heterogeneous environ- ments. Novel tools from molecular biology and emerging developments in NMR instru- mentation and methodology combine to poise the field at a stage where new knowledge and understanding about membrane proteins are ready to be harvested. New Materials. The development of new materials is limited less by synthetic chemistry than by our current ability to characterize the structure, molecular dynamics, chemical kinetics, and reactivity of products. A unique feature of NMR is its ability to characterize samples in various condensed matter states, from liquids to mesophases (such as liquid crystals and biological membranes) to solids. New materials of interest include structural composites, coatings, and catalysts, and each presents great challenges for their characterization. For NMR, sensitivity is, once again, of paramount importance. Surface, rather than bulk samples, by definition, will provide fewer nuclei to be observed, but recent developments in the methods of dynamic nuclear polarization and optically pumped polarization transfer promise greatly enhanced NMR sensitivity from surfaces. Today, precise control and manipulation of material architecture
on the atomic scale are fundamentally important. Lessons learned
from biological systems and manipulation of biological systems
to produce materials of interest are active arenas for research.
Despite much effort, such synthetic and semisynthetic materials
are typically heterogeneous in nature, and NMR is virtually the
only high resolution tool that can be used when sample heterogeneity
is significant. Even natural materials such as the remarkably
strong and flexible fibers of silk, are heterogeneous, and although
silk was recognized early on as being predominantly -sheet Technological Requirements Collaboratories are built upon partnerships, where each partner contributes unique and complementary expertise and also gains from the multiplicative benefits of teaming. A set of communication or collaboratory tools makes communication easier, facilitating the partners' work toward the NMRC's scientific and educational goals. Existing technology can be used to enable the sharing of laboratory notebooks (containing the goals and experimental design, protocols used, raw data, analyzed data and interpretation) in formats that are easy for each partner to appreciate and understand. Clear communication across disciplinary boundaries facilitates the successful use of instrumentation facilities by scientists who have systems that can benefit from such analysis, but do not necessarily have the technological expertise. In order to address problems of protein folding, gene regulation, and protein synthesis, scientific communities are increasingly dependent on large scale facilities like synchrotron and neutron beam lines. Sophisticated technologies such as mass spectrometry and NMR at high magnetic fields build upon advances in biological technologies such as gene sequencing and efficient cloning and expression strategies for protein production including strategic isotope labeling. Ultimately, the information obtained through experimental measurements has to be analyzed and integrated using computational tools in order to develop a picture of how biomolecules function in a coordinated manner in their complex environs. To achieve this level of understanding, it is increasingly important for scientists from different disciplines and with different expertise to be able to network, communicate, and share their expertise and knowledge. Several major efforts worldwide are focused on the development of high field superconducting magnets that will lead to installation within the next 12 months of high resolution magnets (21.1 tesla) that will resonate protons at 900 MHz. The cost of such magnets increases nearly exponentially with field strength (Figure 1). To go significantly beyond 900 MHz will require advances in magnet design and the development of new superconducting wires, both of which have high development costs. High temperature superconducting coils are being developed at the National High Magnetic Field Laboratory (NHMFL) and elsewhere to function in a 20 T background field so that stable superconducting magnets of 1000+ MHz (equivalent to 1+ GHz) class are possible, but again at substantial cost. In parallel to these developments in superconducting magnet technology, magnet laboratories around the world are pursuing improvements in the homogeneity and stability of resistive magnets so that they can be used for a broader range of NMR experiments. At the NHMFL, for example, 1 ppm stability in a 20 MW DC power supply has been demonstrated, and efforts are underway to achieve 1 ppm homogeneity over a spherical volume with a 1 cm diameter at 25 T (1066 MHz). NMR sensitivity has steadily increased over the past three decades, in part due to increased field strength, but also due to the substantial improvements in spectrometer and probe hardware. The first high temperature superconducting radio-frequency (RF) coil NMR probes have been delivered, and although they have limited capabilities and applications, their factor of 5 improvement in sensitivity indicates much promise. Indeed, cryogenically-cooled RF probes and preamplifiers may generate as much sensitivity while maintaining current capabilities. Such improvements are awesome: An experiment that currently takes a day could be done in one hour; samples that precipitate at 200 µ could be observed at 40 µM where they are soluble; the cost of labeled samples would be lowered by a factor of five, and weak signals, currently undetectable in spectra of larger biomolecules could be observed reliably. Other approaches to sensitivity enhancement such as dynamic nuclear polarization, polarization transfer from optically pumped probes, and implementation of microcoils are also being developed. Recently, promising improvements in resolution have been observed in magic angle spinning spectra. Samples such as lipid bilayers that have substantial but anisotropic molecular motions now give rise to very sharp resonances. Other samples carefully prepared so as to generate a very homogenous sample and studied using a probe designed to avoid susceptibility artifacts have also given rise to sharp resonances. Narrow linewidths yield increased signal to noise, and the improved resolution in such spectra allows for the study of much more complicated molecules. Much more can be gained with probe, console, and magnet developments. An order of magnitude improvement in sensitivity will revolutionize NMR as we know it today, opening many new application opportunities through an array of NMR technologies. Resources for the NMRC Instrumentation for the collaboratorium could be purchased from a variety of vendors, but compatibility across the collaboratorium would be absolutely essential. Experiments developed in one laboratory need to be easily implemented on the instruments of other Sectors with minimal delay. It will be important to push for rapid development of data exchange formats and interoperability of various software packages used across the Collaboratorium for data collection, storage processing, and analysis. Exchanging information and shared resources are fundamental for each Sector to fulfill its responsibility to reach out to the latent community of scientists who have important scientific problems in hand, but not the necessary NMR technological expertise. Each Sector, therefore, has an educational mission to make state-of-the-art technology accessible to scientists without such expertise. Users who approach one Sector should be transferred to another if there is more appropriate instrumentation or expertise for this problem elsewhere within the Collaboratorium. Access to one Sector means access to all Sectors. Partnerships with industry both in the arenas of applications and technology are needed. Technological developments need to be transferred efficiently to industry for product development. Spectroscopic developments need also to be transferred for attacking a diversity of problems from synthetic polymers to drug development, to the synthesis and characterization of efficient catalysts. The applications in science performed at the NMRC Sectors need to span the range of frontiers to which the next generation magnetic resonance technology can contribute. This report documents some of those frontiers from new materials, including polymer science and surface chemistry; to protein structure, dynamics and folding; to membrane proteins and other proteins that occur in heterogeneous and complex environments; to nucleic acids and polysaccharides. The diversity of interdisciplinary frontiers demands that the Collaboratorium include and foster a broad range of magnetic resonance technologies, from solution to solid state, from imaging to diffusion measurements, and from spin physics to hardware development. Unique techno- logical areas, such as dynamic nuclear polarization and optical pumping that could lead to significant enhancements in sensitivity and resolution, need to be represented. In addition, laboratories where state-of-the-art RF technology for NMR probes and consoles are being developed need to be incorporated into the NMRC. It is critical to pursue developments in NMR technology in parallel with supporting technology that will lead to enhanced application of the NMR spectroscopy. Some of the key areas for development and coupling are: Sample production and isotope labeling. For biomolecular applications it is critical to develop and exploit methods for production of samples, and the most flexible isotope labeling schemes. Over the past decade such efforts have extended the molecular weight range over two fold, and significant further enhancements are likely, such as single site labeling through biosynthetic mechanisms, uniform labeling of domains in an unlabeled background and cell free biosynthesis. Both Europe and Japan are planning to have isotope labeling facilities. Such a facility in the U.S. should be part of the Collaboratorium. Collaboratorium software and tool development. Communication and collaboration software development activities are vital to the success of the NMRC. Software needs are profound, from remote access of instrumentation, to handling large data sets, to visualization of data, structures, and dynamics models. Software for collaboration and communication among NMR spectroscopists and scientists is extremely important for drawing in the latent community and for maintaining strong ties among the Sectors. In addition, optimized software for data processing and analysis must be shared efficiently. Leading edge magnet technology and science. A powered 35 T (1.5 GHz) medium resolution ( Development of advanced probes for enhanced detection. Since sensitivity remains a key issue, the initial efforts in developing the next generation of probes including cryogenic probes for optimum sensitivity must be vigorously pursued in the context of many different applications. This effort will require development of new designs and materials. Pulse sequence development. Throughout the history of NMR, major advances have arisen through the development of new concepts in manipulation of spins and optimization of pulse sequences. There are already new ideas that build specifically on effects seen at very high fields, and it is critical that the NMRC Sectors continue to develop and extend these. Development of new experimental strategies. NMR is a technique still in a rapid phase of growth. Within the last few years the types of experiments conducted and modes of analysis adopted have changed dramatically. Even at 17T, new experimental strategies have begin to emerge. For example, residual dipolar coupling from field induced molecular orientation is beginning to be used to great benefit in structural biology; interference effects that dramatically narrow lines are being exploited and techniques from other disciplines such as optical pumping are being adopted to improve sensitivity. New opportunities will certainly arise as fields increase. It is important to devote the focus of some Sectors to basic development of NMR spectroscopic techniques. It is envisioned that efforts in these key areas, and in others as well, will be distributed across the array of NMRC Sectors, with focal centers where local expertise is positioned to drive the development activities. The collaboratory nature of the organization will quickly and widely distribute the advances achieved in the Sectors, and, as a result, promote the synergy that is inherent in the Collaboratorium and essential to its success. |
-amyloid, the putative cause of Alzheimer's disease, also have
been studied by solid-state NMR. 
0.1 ppm) magnet system needs to be developed. While such a magnet
will not be suitable for all applications, a broad range of high
field phenomena could be pursued so that the challenges and advantages
of high field NMR can be anticipated. A high resolution 25 T superconducting
magnet that advances the use of high temperature superconductors
for insert coils also needs to be developed.