Protein degradation by human 20S proteasomes elucidates the interplay between peptide hydrolysis and splicing.

If and how proteasomes catalyze not only peptide hydrolysis but also peptide splicing is an open question that has divided the scientific community. The debate has so far been based on immunopeptidomics, in vitro digestions of synthetic polypeptides as well as ex vivo and in vivo experiments, which could only indirectly describe proteasome-catalyzed peptide splicing of full-length proteins. Here we develop a workflow-and cognate software - to analyze proteasome-generated non-spliced and spliced peptides produced from entire proteins and apply it to in vitro digestions of 15 proteins, including well-known intrinsically disordered proteins such as human tau and α-Synuclein.

Nonsense-Mediated mRNA Decay Deficiency Affects the Auxin Response and Shoot Regeneration in Arabidopsis.

Plants generally possess a strong ability to regenerate organs; for example, in tissue culture, shoots can regenerate from callus, a clump of actively proliferating, undifferentiated cells. Processing of pre-mRNA and ribosomal RNAs is important for callus formation and shoot regeneration. However, our knowledge of the roles of RNA quality control via the nonsense-mediated mRNA decay (NMD) pathway in shoot regeneration is limited.

Modelling of polyhydroxyalkanoate synthase from Aquitalea sp. USM4 suggests a novel mechanism for polymer elongation.

Polyhydroxyalkanoate (PHA) synthase, PhaC, is a key enzyme in the biosynthesis of PHA, a type of bioplastics with huge potential to replace petroleum-based plastics. While two structures have been determined, the exact mechanism remains unclear partly due to the absence of a tunnel for product passage. A model of the class I PhaC from Aquitalea sp.