Shift work: The new NMR technique, instant homonuclear decoupling, which is achieved by slice‐selective homo‐decoupling during acquisition, yields pure‐shift NMR spectra (see picture) which can be recorded like regular 1D spectra. No special data processing is necessary and this approach can also be easily adapted for the direct dimension of two‐ and multidimensional spectra, giving improved resolution.

Sam68 and T-STAR are members of the STAR family of proteins that directly link signal transduction with post-transcriptional gene regulation. Sam68 controls the alternative splicing of many oncogenic proteins. T-STAR is a tissue-specific paralogue that regulates the alternative splicing of neuronal pre-mRNAs. STAR proteins differ from most splicing factors, in that they contain a single RNA-binding domain. Their specificity of RNA recognition is thought to arise from their property to homodimerize, but how dimerization influences their function remains unknown. Here, we establish at atomic resolution how T-STAR and Sam68 bind to RNA, revealing an unexpected mode of dimerization different from other members of the STAR family. We further demonstrate that this unique dimerization interface is crucial for their biological activity in splicing regulation, and suggest that the increased RNA affinity through dimer formation is a crucial parameter enabling these proteins to select their functional targets within the transcriptome.

Protein import into peroxisomes relies on the import receptor Pex5, which recognizes proteins with a peroxisomal targeting signal 1 (PTS1) in the cytosol and directs them to a docking complex at the peroxisomal membrane. Receptor-cargo docking occurs at the membrane-associated protein Pex14. In human cells, this interaction is mediated by seven conserved diaromatic penta-peptide motifs (WXXX(F/Y) motifs) in the N-terminal half of Pex5 and the N-terminal domain of Pex14. A systematic screening of a Pex5 peptide library by ligand blot analysis revealed a novel Pex5-Pex14 interaction site of Pex5. The novel motif composes the sequence LVAEF with the evolutionarily conserved consensus sequence LVXEF. Replacement of the amino acid LVAEF sequence by alanines strongly affects matrix protein import into peroxisomes in vivo. The NMR structure of a complex of Pex5-(57–71) with the Pex14-N-terminal domain showed that the novel motif binds in a similar α-helical orientation as the WXXX(F/Y) motif but that the tryptophan pocket is now occupied by a leucine residue. Surface plasmon resonance analyses revealed 33 times faster dissociation rates for the LVXEF ligand when compared with a WXXX(F/Y) motif. Surprisingly, substitution of the novel motif with the higher affinity WXXX(F/Y) motif impairs protein import into peroxisomes. These data indicate that the distinct kinetic properties of the novel Pex14-binding site in Pex5 are important for processing of the peroxisomal targeting signal 1 receptor at the peroxisomal membrane. The novel Pex14-binding site may represent the initial tethering site of Pex5 from which the cargo-loaded receptor is further processed in a sequential manner.

Broadband homonuclear decoupling of proton spectra, that is, the collapse of all multiplets into singlets, has the potential of boosting the resolution of ¹H NMR spectra. Several methods have been described in the last 40 years to achieve this goal. Most of them can only be applied in the indirect dimension of multi‐dimensional NMR spectra or special data processing is necessary to yield decoupled 1D proton spectra. Recently, complete decoupling of proton spectra during acquisition has been introduced; this not only significantly reduced the experimental time to record these spectra, but also removed the need for any sophisticated processing schemes. Here we present an introduction and overview of the techniques and applications of broadband proton‐decoupled proton experiments.

The inherent cytotoxicity of aberrantly folded protein aggregates contributes substantially to the pathogenesis of amyloid diseases. It was recently shown that a class of evolutionary conserved proteins, called MOAG-4/SERF, profoundly alter amyloid toxicity via an autonomous but yet unexplained mode. We show that the biological function of human SERF1a originates from its atypical ability to specifically distinguish between amyloid and nonamyloid aggregation. This inherently unstructured protein directly affected the aggregation kinetics of a broad range of amyloidogenic proteins in vitro, while being inactive against nonamyloid aggregation. A representative biophysical analysis of the SERF1a:α-synuclein (aSyn) complex revealed that the amyloid-promoting activity resulted from an early and transient interaction, which was sufficient to provoke a massive increase of soluble aSyn amyloid nucleation templates. Therefore, the autonomous amyloid-modifying activity of SERF1a observed in living organisms relies on a direct and dedicated manipulation of the early stages in the amyloid aggregation pathway.