This paper explores a method for determining the solution structure of a solvent-exposed polypeptide segment (the L3 loop), which is next to the active site of the penicillin-degrading enzyme IMP-1. Tagging three different sites on the protein with paramagnetic metal ions allowed positioning of the L3 loop with atomic resolution. It was found that the method was more robust when omitting data obtained with different metal ions if obtained with the same tag at the same tagging site.

Through the advent of fast magic-angle spinning and high magnetic fields, the spectral resolution of solid-state NMR spectra has recently been greatly improved. To take full advantage of this gain, the magnetic field must be stable over the experiment time of hours or even days. We thus monitor the field by simultaneous acquisition of a frequency reference (SAFR) and use this information to correct multidimensional spectra improving resolution and availability of productive magnet time.

This work provides some clarifications on the long-known Redfield theory of spin relaxation, which considers a small system coupled to a large ensemble of particles in thermodynamic equilibrium. The derivation is rewritten so as to emphasize the usual assumptions and their consequences. In particular, the respective roles of the detailed balance balance assumption and the non-commutativity of the spin–bath coupling are discussed.

Strong signals in nuclear magnetic resonance are perturbed by their feedback interaction with the radio frequency circuit, a phenomenon known as radiation damping. This effect is usually weak and only influences the signals that are at its source. In this work, it is shown that, under certain circumstances, radiation damping can have far-reaching consequences.

In contrast to adiabatic excitation, recently introduced SORDOR-90 pulses provide effective transverse 90° rotations throughout their bandwidth, with a quadratic offset dependence of the phase in the x,y plane. Together with phase-matched SORDOR-180 pulses, this enables a direct implementation of the Böhlen–Bodenhausen approach for frequency-swept pulses for a type of 90°/180° pulse–delay sequence. Example pulse shapes are characterised, and an application is given with a 19F-PROJECT experiment.

Installing a tag containing a paramagnetic metal ion on a protein can lead to large changes (pseudocontact shifts) in the resonances observed in NMR spectra. These are easily measured and contain valuable long-range structural information. The present work shows that a single tagging site furnished with different tags can be sufficient to localise atoms in proteins with high accuracy. In fact, this strategy works almost as well as the same number of tags distributed over multiple tagging sites.

We have presented a CMOS-based NMR platform featuring arbitrary phase control and coherent detection in a non-zero intermediate frequency (IF) receiver architecture as well as active automatic temperature compensation. The proposed platform is centered around a custom-designed NMR-on-a-chip transceiver. The entire system achieves a phase stability well below 1° in consecutive pulse acquire experiments and keeps a normalized standard deviation in the measured T2 values of 0.45 % over 100 min.