Volume 14 Issue 6, June 2018

Catalytic activity is a critical protein function, but its natural evolution has never been observed. Researchers have now revealed the mutations and biochemical mechanisms by which two ancient nonenzymatic proteins acquired catalytic activity.

Variation in nutrient availability is a common challenge facing living organisms. Analysis of metabolomic and fluxomic responses in cyanobacteria to changes in nitrogen availability has led to the discovery of an ornithine–ammonia cycle.

Fast, single-molecule tracking microscopy monitors transitions between mobile and ribosome-bound fluorescent tRNAs to achieve nucleotide-resolution measurements of translation rates in living cells.

Synthetic biology offers innovative approaches for engineering biological systems, but also supports the development of biocontainment strategies that ensure the safe application of genetically modified organisms.

The structure of a monotopic polyprenol phosphate phosphoglycosyl transferase, PglC, reveals how it interacts with the bacterial membrane and coordinates a reaction between membrane-embedded and soluble substrates during glycoconjugate assembly.

Ancestral protein reconstruction, with structural and biochemical analysis, illustrates the evolution of a solute-binding protein to cyclohexadienyl dehydratase through incorporation of a catalytic residue and gradual reshaping of the binding site.

Ancestral sequence inference, directed evolution, structural analysis, NMR, and molecular dynamics simulations illuminate how enantioselective activity arises during the evolutionary trajectory of chalcone isomerase from a noncatalytic ancestor.

A β-lactamase, a novel type of amidase, and the phenylacetic acid catabolon comprise a catabolic pathway, revealed by genomic and transcriptomic analysis, that enables multiple soil bacteria to use β-lactam antibiotics as a carbon source.

Single-molecule measurements of DNA gyrase activity reveal conformational dynamics coupling ATP consumption to DNA supercoiling.

An ornithine–ammonia cycle involving an arginine dihydrolase was identified in cyanobacteria. This cycle serves as a conduit in the nitrogen storage-and-remobilization machinery and enables cellular adaptation to nitrogen fluctuations.

A phage-derived peptide selectively binds to the Frizzled 7 CRD resulting in disruption of the dimer interface and impairing Wnt/β-catenin stem signaling in intestinal organoids.

The monomeric near-infrared (NIR) fluorescent protein miRFP720 enables development of fully NIR Förster resonance energy transfer (FRET) biosensors compatible with CFP–YFP FRET biosensors and blue–green optogenetic tools without optical cross-talk.

Use of a combined Tn-seq and machine-learning approach for predicting mechanisms and targets of antibiotic action in Staphylococcus aureus shows that the natural product lysocin E (LysE) binds Lipid II on the cell surface and damages the membrane.

ABP profiling identifies uncharacterized S. aureus serine hydrolases, including the surface-localized FphB, which processes lipid ester substrates and is required for infection in vivo. An FphB inhibitor reduces in vivo bacterial load.

Combination of single-molecule tracking experiments and machine-learning approaches to monitor diffusional state transitions between ribosome-bound and free tRNAs allows codon resolution measurements of translation kinetics.

The GlycoSCORES method, which involves cell-free protein expression and substrate-site profiling of glycosyltransferase enzymes by SAMDI–MS, enables the identification of glycosylation tags for glycoengineering efforts.