Insights into the Interaction Landscape of the EVH1 Domain of Mena.

The Enabled/VASP homology 1 (EVH1) domain is a small module that interacts with proline-rich stretches in its ligands and is found in various signaling and scaffolding proteins. Mena, the mammalian homologue of Ena, is involved in diverse actin-associated events, such as membrane dynamics, bacterial motility, and tumor intravasation and extravasation. Two-dimensional (2D) H-N HSQC NMR was used to study Mena EVH1 binding properties, defining the amino acids involved in ligand recognition for the physiological ligands ActA and PCARE, and a synthetic polyproline-inspired small molecule (hereafter inhibitor ).

Author Correction: Second-generation DNA-templated macrocycle libraries for the discovery of bioactive small molecules.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Substrate-selective inhibitors that reprogram the activity of insulin-degrading enzyme.

Enzymes that act on multiple substrates are common in biology but pose unique challenges as therapeutic targets. The metalloprotease insulin-degrading enzyme (IDE) modulates blood glucose levels by cleaving insulin, a hormone that promotes glucose clearance. However, IDE also degrades glucagon, a hormone that elevates glucose levels and opposes the effect of insulin.

Improving cytidine and adenine base editors by expression optimization and ancestral reconstruction.

Base editors enable targeted single-nucleotide conversions in genomic DNA. Here we show that expression levels are a bottleneck in base-editing efficiency. We optimize cytidine (BE4) and adenine (ABE7.

Structure-Based Design of a Eukaryote-Selective Antiprotozoal Fluorinated Aminoglycoside.

Aminoglycosides (AG) are antibiotics that lower the accuracy of protein synthesis by targeting a highly conserved RNA helix of the ribosomal A-site. The discovery of AGs that selectively target the eukaryotic ribosome, but lack activity in prokaryotes, are promising as antiprotozoals for the treatment of neglected tropical diseases, and as therapies to read-through point-mutation genetic diseases. However, a single nucleobase change A1408G in the eukaryotic A-site leads to negligible affinity for most AGs.

Second-generation DNA-templated macrocycle libraries for the discovery of bioactive small molecules.

DNA-encoded libraries have emerged as a widely used resource for the discovery of bioactive small molecules, and offer substantial advantages compared with conventional small-molecule libraries. Here, we have developed and streamlined multiple fundamental aspects of DNA-encoded and DNA-templated library synthesis methodology, including computational identification and experimental validation of a 20 × 20 × 20 × 80 set of orthogonal codons, chemical and computational tools for enhancing the structural diversity and drug-likeness of library members, a highly efficient polymerase-mediated template library assembly strategy, and library isolation and purification methods. We have integrated these improved methods to produce a second-generation DNA-templated library of 256,000 small-molecule macrocycles with improved drug-like physical properties.

Toxicity modulation, resistance enzyme evasion, and A-site X-ray structure of broad-spectrum antibacterial neomycin analogs.

Aminoglycoside antibiotics are pseudosaccharides decorated with ammonium groups that are critical for their potent broad-spectrum antibacterial activity. Despite over three decades of speculation whether or not modulation of pKa is a viable strategy to curtail aminoglycoside kidney toxicity, there is a lack of methods to systematically probe amine-RNA interactions and resultant cytotoxicity trends. This study reports the first series of potent aminoglycoside antibiotics harboring fluorinated N1-hydroxyaminobutyryl acyl (HABA) appendages for which fluorine-RNA contacts are revealed through an X-ray cocrystal structure within the RNA A-site.

Anti-diabetic activity of insulin-degrading enzyme inhibitors mediated by multiple hormones.

Despite decades of speculation that inhibiting endogenous insulin degradation might treat type-2 diabetes, and the identification of IDE (insulin-degrading enzyme) as a diabetes susceptibility gene, the relationship between the activity of the zinc metalloprotein IDE and glucose homeostasis remains unclear. Although Ide(-/-) mice have elevated insulin levels, they exhibit impaired, rather than improved, glucose tolerance that may arise from compensatory insulin signalling dysfunction. IDE inhibitors that are active in vivo are therefore needed to elucidate IDE's physiological roles and to determine its potential to serve as a target for the treatment of diabetes.

Crystal structures of a bioactive 6'-hydroxy variant of sisomicin bound to the bacterial and protozoal ribosomal decoding sites.

Parasitic infections recognized as neglected tropical diseases are a source of concern for several regions of the world. Aminoglycosides are potent antimicrobial agents that have been extensively studied by biochemical and structural studies in prokaryotes. However, the molecular mechanism of their potential antiprotozoal activity is less well understood.

Toward Overcoming Staphylococcus aureus Aminoglycoside Resistance Mechanisms with a Functionally Designed Neomycin Analogue.

Deoxygenation of the diol groups in rings A and D of neomycin in combination with the introduction of an N1-(l)-HABA group in the 2-deoxystreptamine subunit (ring B) leads to a novel and potent antibiotic (1) with activity against strains of S. aureus carrying known aminoglycoside resistance determinants, as well as against an extended panel of Methicillin-resistant S. aureus isolates (n = 50).

Hybrid aminoglycoside antibiotics via Tsuji palladium-catalyzed allylic deoxygenation.

Biosynthetically inspired manipulation of the antibiotic paromomycin led, in six high-yielding steps, to a ring A harboring an α,β-unsaturated 6'-aldehyde and an allylic 3'-methylcarbonate group. Tsuji deoxygenation in the presence of 5 mol % Pd(2)(dba)(3) and Bu(3)P granted access to a novel series of 3',4'-dideoxy-4',5'-dehydro ring A hybrids. The neomycin-sisomicin hybrid exhibited superior in vitro antibacterial activity to the parent compound neomycin.

Biomimetic synthesis and structural refinement of the macrocyclic dimer aminoglycoside 66-40C--the remarkably selective self-condensation of a putative aldehyde intermediate in the submerged culture medium producing sisomicin.

Aminoglycoside 66-40C, an unprecedented 16-membered bis-azadiene macrocyclic natural product isolated from the Micromonospora producer of the antibiotic sisomicin, was synthesized following a biomimetic strategy which definitively established its origin as arising from a remarkably selective non-enzymatic macro-dimerization.