Volume 16 Issue 9, September 2020

Thermodynamic principles are used to map the phase behavior of a tunable protein-binding system under crowded cellular conditions. This study marks a substantial step forward in relating molecular interactions to material properties and cellular processes involving protein self-assembly.

It is generally believed that large protein complexes provide a catalytic advantage due to substrate channeling between enzymatic domains. However, the structure and function of the pentafunctional AROM complex suggests a noteworthy exception.

An NMR method to monitor conformational states of challenging large protein targets is described. The method, which can be used to evaluate distances between two labels and to measure conformational exchange rates, revealed an unanticipated outward-facing state in a glutamate transporter.

A synthetic phase separation system consisting of two protein components with tunable parameters was developed to visualize and characterize phase diagrams in living cells, revealing that increasing the interaction affinity enhances phase separation and the viscosity of condensates in vivo.

Single-molecule and super-resolution approaches define a monomer–dimer equilibrium of µ-opioid receptors and show that receptors form agonist-induced dimers coincident with β-arrestin2 binding to receptors.

Imaging studies revealed that m⁶A-binding YTHDF proteins promoted phase separation of core proteins of stress granules by reducing the critical size and activation energy barrier, thus promoting the formation of stress granules in cells.

A combination of tRNA sequencing and mass spectrometry was developed to profile tRNA modification enabling identification of a new modification acacp³U and the presence of cytosine-to-pseudouracil RNA editing in Vibrio cholerae.

Structural, conformational and biochemical characterization of the AROM complex and its constituent shikimate pathway domains reveals how the complex balances compactness and conformational freedom, yet does not benefit from substrate channeling.

A highly selective covalent peptide inhibitor of the peptidyl-prolyl cis/trans isomerase NIMA-interacting 1 (Pin1) is used to show that Pin1 cooperates with mutant KRAS to promote pancreatic ductal adenocarcinoma (PDAC) transformation.

Engineering cleavage sites into gas vesicle proteins enables protease-responsive regulation of gas vesicle mechanics and activates them as ultrasound contrast agents for imaging applications in cells and living mice.

Activity-based protein profiling (ABPP) was used to identify and optimize bioactive, selective pharmacological enzyme activators of the serine hydrolase LYPLAL1, which improved the metabolic defects of diet-induced obese mice.

A ¹⁹F-NMR-based method monitoring the conformational dynamics of the glutamate transporter GltPh identified one inward- and two outward-facing states, including one unanticipated outward-facing state that was characterized by cryo-EM.

BotH is an unusual α/β-hydrolase-fold enzyme that catalyzes epimerization of an aspartate residue during bottromycin biosynthesis via a mechanism distinct from other known peptide natural product epimerases.

A structural and biochemical study of bacterial β-barrel assembly machinery component BamA with transport substrate RcsF shows an inward-open conformation with RcsF trapped inside the β-barrel lumen and suggests a push–pull substrate export mechanism.

An econometric model built on regulatory networks and calibrated by proteomics data identifies nonessential transcription factors that when deleted in Escherichia coli result in a strain with an expanded proteome for engineering applications.