Volume 13 Issue 4, April 2017

Systematically modifying biological assembly lines for the synthesis of novel products remains a challenge. Structural insights and computational modeling have now paved the way for efficient redesigns of giant fatty acid synthases.

New small-molecule inhibitors of the histone methyltransferase PRC2 interfere with the allosteric activation of enzymatic activity. These compounds are effective against PRC2-dependent tumors that are resistant to catalytic inhibitors and provide important new tools for altering chromatin regulation.

Pharmacological chaperones are small drugs that stabilize a protein's fold and are being developed to treat diseases arising from protein misfolding. A mathematical framework to model their activity in cells enables insight into their mechanism and capacity to rescue protein foldedness.

In early-stage developing neurons, the cAMP–PKA (protein kinase A) signaling pathway is strongly inhibited. This negative control is later removed, unleashing cAMP–PKA signaling, particularly in distal axonal parts, thus allowing for axonal growth.

A review of the roles of cyclic dinucleotides (CDNs) in signaling systems including transcription, ion transport, bacterial secretion and eukaryotic immune responses, highlighting the diverse binding modes of CDNs by target proteins and functional insights gained from structural studies.

Integration of heterologous enzymes into the reaction chambers of fungal fatty acid synthases (FASs) demonstrates the capacity of these megaenzymes for engineered production of short- and medium-chain fatty acids and methyl ketones.

In vitro and in silico analysis enables the rational design of fatty acid synthase (FAS)-mediated pathways for the compartmentalized production of desirable fatty acids and a polyketide lactone.

Discovery and characterization of an unusually permissive C-prenyltransferase provides a biocatalytic route for generating novel prenylated compounds, including daptomycin derivatives with increased potency.

Pharmacological chaperones improve folding of destabilized Escherichia coli dihydrofolate reductase (DHFR) and human disease-linked α-galactosidase A (α-GAL) by biasing the kinetic partitioning between folding, aggregation, and degradation. Chaperoning spares DHFR from aggregation and α-GAL from degradation.

Optimizing the signal-to-noise ratio in time-resolved FRET through generation of agonist-responsive cell-surface receptor biosensors, including GABA_B receptors and EGFR, which are useful for monitoring conformational changes associated with receptor activation.

H3K27me3 binding to the EED pocket of the Polycomb repressive complex 2 (PRC2) is required to activate PRC2. An allosteric small-molecule inhibitor of PRC2 was identified that binds to the EED pocket and blocks PRC2 methyltransferase activity in cells.

A pyrrolidine-based small-molecule inhibitor competes with H3K27me3 for binding to EED leading to inactivation of PRC2 and global reduction in H3K27me3 levels.

Reconstitution experiments using substrates prepared by chemoenzymatic synthesis demonstrate that three LCP family proteins catalyze the ligation of wall teichoic acids to peptidoglycan in the biosynthesis of the Staphylococcus aureus cell wall.

Spectroscopic studies of allosteric activation of Aurora A kinase using a site-specific infrared probe combined with FRET analysis and molecular dynamics simulations reveals a water-mediated hydrogen bond network in the active site that regulates Aurora A activity.

The Ni(ii) affinity of Ni(ii) sensor InrS is attuned to buffered Ni(ii) concentrations, explaining why these two parameters co-vary for different metals over many orders of magnitude.

Metabolic labeling of the cell surface with a caged azide sugar enabled cleavage-mediated activation by enzymes overexpressed in cancer cells, allowing enhanced targeted delivery of a doxorubicin conjugate through copper-free click chemistry.

A gradient of cAMP in developing hippocampal neurons that is important for axon elongation is shaped by spatial differences in phosphodiesterase localization and is maintained by AKAP-anchored PKA, as revealed by using FRET-based biosensors.

Design of a proximity-dependent split RNA polymerase system and its optimization by phage-assisted continuous evolution (PACE) enabled the development of a family of activity-dependent split RNA polymerase biosensors regulated by small molecules or light.

Experimental work and computational modeling together reveal a suite of catalytic roles of the GlcN6P cofactor in the glmS ribozyme, including activation of the nucleophile, electrostatic stabilization, and alignment of the active site.

In Escherichia coli, replacement of the endogenous tryptophanyl–tRNA synthetase–tRNA pair with its counterpart from Saccharomyces cerevisiae liberates the bacterial counterpart for directed evolution to incorporate unnatural amino acids in both E. coli and eukaryotes.