Spin relaxation in NMR spectroscopy is a powerful approach for probing aspects of conformational dynamics in biological macromolecules. Methods for characterizing dynamics on picosecond-nanosecond and on microsecond-millisecond time scales, emphasizing the information content provided by multiple static magnetic fields, are illustrated by applications to the enzyme ribonuclease H and the yeast...
Pseudocontact shift (PCS) NMR is a powerful tool to gain long-range structural information on protein-protein and protein-ligand interactions. We have shown the localization of three different fluorine containing high affinity ligands within the 30 kDa enzyme human carbonic anhydrase using only 19F PCS NMR [1]. The distances between the 19F atoms and the lanthanide cations ranged...
Measuring transverse relaxation rates provides insight into the dynamics of molecules. For example, measurements of relaxation dispersion allow the study of invisible conformations of proteins. Such applications are currently restricted to sparse spin systems in which homonuclear couplings can be neglected, such as 15NH or selectively labelled 13CHD2 groups in proteins. The accurate...
The coordinates of a nuclear spin relative to a lanthanide ion can be determined with high accuracy in a system, where a paramagnetic lanthanide tag is attached to a protein of known three-dimensional structure. First, pseudocontact shifts (PCS) of the protein are measured by NMR to determine the coordinate frame of the magnetic susceptibility anisotropy (DeltaChi) tensor associated with the...
The interaction of the N-terminal domain of huntingtin exon-1 with membrane surfaces promotes poly-glutamine mediated aggregation, and is thought to play a role in the etiology of Huntington’s disease. We investigated the kinetics of binding of two huntingtin peptides, comprising the 16-residue N-terminal amphiphilic domain alone (httNT) and with a seven residue poly-glutamine C-terminal tract...
GPCRs belong to a family of ca. 850 plasma membrane-embedded proteins, which as molecular signalling switches control a wide range of physiological processes in health and disease. Activation of the individual receptor proteins is initiated via extracellular stimuli, such as photon uptake, or binding of small molecules, peptides, proteins, ions, lipids etc. This initial stimulus leads to...
Reversibly photo-switchable fluorescent proteins (RSFPs) are important tools for microscopy and other biotechnological applications. They are currently routinely used for Near-Field Super Resolution Microscopy techniques, e.g. RESOLFT (1). Their characteristic switching between a fluorescent “on” state and a non-fluorescent “off” state, combined with signal processing algorithms has allowed to...
In contrast to most proteins, RNAs can adopt more than one conformational state of similar stability. The different stable conformations are directly linked to the RNA’s biological function. Examples for such functional multi-state RNAs are riboswitches, ribozymes and RNA thermometers, where either external factors such as small molecular metabolites and temperature or the intrinsic...
Sensitivity and resolution have been the two important traits in NMR of biomolecules. With the advent of cryogenically cooled probed and non-uniform sampling methods, the battle of sensitivity and resolution has to be revisited. 1H has long enjoyed the limelight due to its inherent sensitivity. The large gyromagnetic ratio of 1H it is nemesis when dealing high molecular weight systems since...