NMR for Biological Systems
CERM - UniFi - Firenze
Description
Nuclear Magnetic Resonance (NMR) spectroscopy is a strategic tool for studying a variety biomolecular systems, providing a wealth of information at the atomic level. Using NMR, a wide range of observables, including chemical shift values, nuclear spin relaxation rates, exchange effects, and diffusion coefficients can be measured to obtain structural and dynamic details on a biomolecule.
This technology has a wide range of applications, allowing for example the determination of the three-dimensional structures of proteins at high resolution, the elucidation of their interaction processes as well as the understanding of complex biological mechanisms such as the role played in different steps of the assembly of molecular machinery. Proteins frequently contain paramagnetic metal ions in their native structure that can complicate their investigation leading to the development and application of experiments tailored for such systems.
Since biomolecules are in constant motion, the observation of their dynamics is essential for a better understanding of their biological role. Solution NMR can provide details of flexibility and conformational dynamics over a wide range of time scales (from picoseconds to days). This puts solution NMR in a unique position compared to other techniques, such as X-ray crystallography, as it also represents a strategic tool for the study of Intrinsically Disordered Proteins (IDPs) in particular with the application of heteronuclear direct detection.
The relaxation properties of biomolecules and other compounds can be investigated using NMR experiments at various fields ranging from high fields (16 T or above) to very low fields (mT or below). These studies, known as relaxometry, provide the understanding of unique physical and chemical properties of many substances.
In addition, NMR offers the possibility of studying biological macromolecules in their native environment, the cell, with in-cell NMR. Observing chemical shift perturbations due to post-translational modifications, interactions with other cellular components, and conformational changes in a living context might be very informative.
Another way to study complex biomolecules at atomic resolution is to exploit solid-state NMR (ssNMR) spectroscopy. This latter technique allows for the investigation of lipid bilayers, membrane proteins, fibrils, protein gels and cell organelles, among other things. ssNMR also represents a basic technique in the study of inorganic compounds allowing for the determination of crystal structures at the atomic level, with the possibility of describing the physical and chemical properties of such materials.
In the context of the -omic sciences, with a particular focus on metabolomics, NMR spectroscopy plays a key role in enabling high-throughput analysis of complex mixtures. NMR spectroscopy is a non-destructive and readily quantifiable technique that limits the sample preparation and the use of preliminary separation techniques. These features make NMR a fast and simple technique for large-scale metabolomics and foodomics studies.
Instruments
The large number of NMR spectrometers located at CERM/CIRMMP, each equipped with one or more probe-heads, allows the most comprehensive range of experiments to be carried out for the structural and dynamic characterization of biological macromolecules.
The following is a list of the NMR spectrometer present in the center:
– 1200 MHz 1H Larmor frequency (28.2 T) equipped with TCI (3 mm) and TXO (5 mm) cryoprobes for solution experiments, with 1H, 13C, 15N channels and 2H decoupling.
– 950 MHz 1H Larmor frequency (22.3 T) equipped with TCI (5 mm) cryoprobe for solution experiments, with 1H, 13C, 15N channels and 2H decoupling.
– 900 MHz 1H Larmor frequency (21.1 T) equipped with TCI cryoprobe (5mm) and TXI room temperature (RT, 5 mm) for solution experiments, with 1H, 13C, 15N channels and 2H decoupling.
– 850 MHz 1H Larmor frequency (20.0 T) equipped with MAS accessories for solid-state experiments (CP MAS DVT 15N, 13C, 1H channels 3.2 mm; CP MAS 1H-19F, BB, 15N channels 1.3 mm, CP MAS 1H/13C/15N 0.7 mm)
– 800 MHz 1H Larmor frequency (18.8 T) equipped with MAS accessories for solid-state experiments (CP MAS DVT low-E 15N, 13C, 1H channels 3.2 mm, CP MAS 1H-19F, BB-X, BB-Y channels 1.3 mm, CP MAS 1H, 13C, 15N channels 1.3 mm); TXI RT (5 mm) for solution experiments with 1H, 13C, 15N channels with 2H decoupling and QXI room temperature (5 mm) with 1H, 13C, 15N 31P channel and 2H decoupling
– 700 MHz 1H Larmor frequency (16.4 T) equipped with TCI cryoprobe (5 mm) and TXI RT probe (5 mm) for solution experiments with 1H, 13C, 15N channels and 2H decoupling. The spectrometer is provided with an autosampler, for the high-throughput analysis of multiple samples.
– 700 MHz 1H Larmor frequency (16.4 T) equipped with TXO cryoprobe (5 mm), TXO RT probe (5 mm) and TXI RT (5 mm) for solution experiments with 1H, 13C, 15N channels and 2H decoupling. The spectrometer is also provided with a fast shuttle system for relaxometry measurements.
– 700 MHz 1H Larmor frequency (16.4 T) equipped with MAS accessories for solid-state experiments (CP MAS 3.2 mm and 4.0 mm with 15N, 13C, 1H channels).
– 600 MHz 1H Larmor frequency (14.1 T) equipped with TXI RT (5 mm) for solution experiments and HR-MAS (4.0 mm) with 1H, 13C, 15N channels and 2H decoupling. Few BB probes which cover a frequency range from 600 to 20 MHz (BBI RT 5 mm, BBO RT 5 mm, BBO RT 10 mm, BBI RT low-γ 10 mm) for solution experiments.
– 600 MHz 1H Larmor frequency (14.1 T) equipped with TXI RT (5 mm) for solution experiment with 1H, 13C, 15N channels and 2H decoupling. The spectrometer is provided with an autosampler for the high-throughput analysis of multiple samples.
– 500 MHz 1H Larmor frequency (11.7 T) equipped with TCI cryoprobe (5 mm), TXI RT (5 mm) with 1H, 13C, 15gt;N channels , TBO RT (5 mm) with 1H, 31P, BB channels and BBI RT (5 mm) for solution experiments.
– 400 MHz 1H Larmor frequency (9.4 T) equipped with BBO RT (5mm), BBI RT (5 mm) with 1H, BB channels and BBI RT (3mm) with 1H, BB channels for solution experiments. The spectrometer is provided with an autosampler for the high-throughput analysis of multiple samples.