Research articles

Some polyketide synthase pathways include branching modules that insert branched monomers into polyketide products. In vitro reconstitution using swapped domains now shows that the mysterious branching (B) domain and the homologous X domain in these modules have structural rather than catalytic roles.

Single-molecule experiments reveal the unfolding and refolding landscape of the rhomboid protease GlpG in a native-like lipid membrane. GlpG unravels cooperatively in a single step and has a large unfolding barrier, making for a long-lived folded state.

Unique activities and high potency at disease-relevant biological targets can now be identified for ‘dark chemical matter’—compounds in high-throughput screening libraries that have been extensively tested but that have never been annotated as having biological activity.

25-Hydroxycholesterol induces expression of the microRNAs miR-130b and miR-185 in HCV-infected cells, and these inhibit viral fatty acid desaturation, lipid uptake and biosynthesis, thereby limiting infection. HCV counteracts this immunometabolic response by downregulating these microRNAs.

The combination of a light-activated receptor tyrosine kinase and a fluorescent MAPK/ERK reporter results in the development of an optogenetics-based cell screening method to identify small-molecule inhibitors of RTK signaling.

The serine protease HTRA1 utilizes a "disintegration" mechanism involving its flexible PDZ domains to first loosen tau amyloid fibrils and subsequently disintegrating the fibrillar core structure for efficient proteolytic degradation.

Gain of function mutations in isocitrate dehydrogenase 1 (IDH1) have been detected in cases of acute myeloid leukemia (AML). The application of an allosteric IDH1 inhibitor in AML cells promotes blast differentiation and restores DNA cytosine methylation patterns.

Structural and biochemical investigations of a xylosyltransferase in complex with a domain from its substrate Notch inform on the catalytic mechanism and the conformational rearrangements needed for substrate binding, while genetic analysis poses new questions in cancer biology.

Crystal structures of the full-length VS ribozyme show a domain-swapped dimer that reveals potential mechanisms for cis and trans processing, and suggest convergent evolution in the active site motifs across multiple ribozymes.

The identification and characterization of two cytochromes P450 from cabbage establish the biochemical basis for synthesizing brassinin-based phytoalexins, using two different routes of S-heterocyclization to construct these important vegetable compounds.

Crystal structure of the Type ISP restriction enzyme−DNA complex and single-molecule studies reveal that DNA cleavage occurs through remodeling of ATPase-DNA interactions resulting in translocation of the enzyme without loop formation.

High-throughput chemical screening identified several groups of compounds that selectively block superoxide production from the outer Q-binding site of mitochondrial complex III and protect against ROS-induced oxidative stress in pancreatic β cells.

Triple combinations of carbapenem, penicillin and β-lactamase inhibitor antibiotic classes are synergistic against MRSA through a mechanism involving allostery-based synergy and collateral sensitivity and can thus be applied at doses that lead to less resistance.

A quantitative chemical proteomics approach identified the DNA damage response mediator 53BP1 as a direct reader of the phosphorylated histone variant γH2AX in cells.

Linking a peptide with a small-molecule ligand for the serum protein transthyretin ensures half-life extension without diminishing potency through protection against proteases and decreasing glomerular filtration.

Enzyme engineering can yield changes in substrate specificity, but limited options exist when mutations are not causing the desired outcome. Selection of monobodies that bind near, but not at, a galactosidase active site now offers another avenue for altering product profiles.

Drug metabolism in humans is typically discussed in terms of P450 reactions, but growing evidence indicates aldehyde oxidase plays a central role as well. The first crystal structures of the human enzyme reveal a flexible tunnel to the active site and a new inhibitory site.

Cellular use of coenzyme A from external sources requires the hydrolysis of extracellular coenzyme A into 4′-phosphopanthetheine, which can cross the membrane. CoA synthase subsequently converts intracellular 4′-phosphopanthetheine into coenzyme A.

Calprotectin sequesters manganese and zinc from bacteria, preventing their growth. Spectroscopic and biological data show it also chelates iron with sub-picomolar affinity using a hexahistidine motif, establishing a new mechanism for its antibacterial activity.

Structural and biophysical evidence demonstrating that glutaredoxin-3 passes [2Fe-2S] clusters to anamorsin during a protein-protein interaction mediated by their N-terminal domains define the early steps of iron-sulfur cluster protein maturation.