Volume 14 Issue 1, January 2018

Modification of folded proteins at will, within any sequence context, remains an elusive goal. A proteome-wide screening approach has now identified a set of protein ligases that enables conjugation of peptides to almost any protein N terminus, overcoming longstanding limitations in protein engineering.

Glycosylation of Notch receptors regulates ligand-induced Notch signaling, which is essential for normal development in animals. Fucose analogs targeting Notch glycosylation serve as ligand-specific Notch inhibitors and facilitate the understanding of how O-glycan regulates Notch–ligand interactions.

Biosynthesis of the antibiotic sulfazecin involves N-sulfonation in trans of the tripeptide intermediate before synthesis of the β-lactam ring by a noncanonical thioesterase domain, demonstrating a new enzymatic route to the azetidinone moiety.

In organohalide-respiring bacteria, reductive dehalogenases cleave carbon–halogen bonds using cobamide prosthetic groups. Desulfitobacterium hafniense uses an unprecedented cobamide variant, which includes unsubstituted purine, for this function.

Ultrasensitive imaging of lanthanide chelates is achieved by integrating transreflected illumination, luminescence resonance energy transfer, and time-resolved microscopy.

Mass-spectrometry-based metabolomics analysis of oligodendrocyte differentiation led to the identification of an endogenous metabolite, taurine, that enhanced the process of drug-induced OPC differentiation.

Strains of Escherichia coli, each expressing a subset of the 34 translation machinery proteins, are grown in synthetic microbial consortia to enable the efficient isolation of the full machinery from a single culturing, lysis, and purification procedure.

A multistage tandem mass spectrometry approach enables the application of native proteomics to characterize intact endogenous protein complexes in discovery mode, including covalent modifications as well as noncovalently bound cofactors and ligands.

Engineering of nonimmune cells with a cell-contact sensor and antigen recognition domains enables cell-contact-dependent sensor cell signaling and effector molecule production directed to attack target cells, providing an alternative strategy to chimeric antigen receptor T-cell (CAR-T) technology.

A comprehensive characterization of peptide ligase specificity using proteome-derived peptide libraries enables the identification of 72 new subtiligases and their application to site-specific bioconjugation and sequencing of the cellular N terminome.

High-throughput screening identified potent small-molecule inhibitors of the endosomal Toll-like receptor TLR8 that stabilize the preformed TLR8 dimer in its resting state by binding to a unique site on the inactive dimer interface.

Protein O-fucosyltransferase 1 (Pofut1) regulates Notch activity by adding O-fucose residues to its extracellular domain. Fucose analogs were identified that inhibited Delta-mediated Notch binding and activation but spared Jagged1-mediated signaling.

Direct conversion of 5-fdC into dC by C–C bond breakage is revealed by metabolic tracing studies through incorporation of synthetic stable isotope- and (R)-2′-fluorine-labeled dC and fdC derivatives into the genome of cultured mammalian cells.

A chemically synthesized analog of Bacillus cereus secondary cell wall polysaccharide (SCWP) facilitates the identification of PatB1 as a SCWP O-acetyltransferase, and the structure of PatB1 provides insights into its catalytic mechanism.

Synthetic beta cells were fabricated through 'vesicles-in-vesicle' liposomal superstructures equipped with glucose-sensing and membrane-fusion machinery, thus enabling sensing of graded glucose levels and secretion of insulin via fusion processes.

The small molecule nitazoxanide (NTZ) was identified as a Wnt inhibitor by promoting protein citrullination of β-catenin through increased cytosolic calcium and PAD2 protein stabilization. β-catenin citrullination results in proteasomal degradation.