Research articles

The biosynthesis of goadvionins—hybrid lipopeptide antibiotics—is not fully understood. An unusual acyltransferase, GdvG, has now been identified and shown to catalyse a condensation reaction between an acyl-carrier-protein-tethered very-long-chain fatty acid and an eight-residue ribosomally synthesized and post-translationally modified peptide. The position of functional groups in the very-long acyl chain have been determined by tandem mass spectrometry.

Using readily accessible tropones and γ-methylidene-δ-valerolactones, the divergent synthesis of three classes of challenging [5.5.0] or [4.4.1] bicyclic systems has been achieved—with high efficiency and stereoselectivity—through Pd-catalysed higher-order cycloaddition. Mechanistic studies and density functional theory calculations indicate that the divergent reactions arise from the different reactivity of two diastereomeric intermediates.

Chemical reactions usually proceed through either a radical, concerted or ionic mechanism; transformations in which all three mechanisms occur are rare. Now, the mechanical dissociation of an N-heterocyclic carbene precursor has been shown to proceed with the rupture of a C–C bond through concomitant heterolytic, concerted and homolytic pathways.

Photoinduced isomerization reactions, including ring-opening reactions, lie at the heart of many chemical processes in nature. The pathway and dynamics of the ring opening of a model heterocycle have now been investigated by femtosecond photoelectron spectroscopy combined with ab initio theory, enabling the visualization of rich dynamics in both the ground and excited electronic states.

Visualization of endogenous G-quadruplexes (G4s) in living cells by fluorescence microscopy has been hampered by the high concentrations of G4-binding probes required, which can artificially induce additional G4 formation. Now, a G4-specific fluorescent probe (SiR-PyPDS) has been developed that enables single-molecule and real-time detection of individual G4 structures in living cells without perturbing G4 formation and dynamics.

Engineering reverse transcriptases for modified or unnatural nucleic acids is challenging, but now a versatile method has been developed that enables the discovery of efficient reverse transcriptases. The method works with a wide range of template structures, including xeno-nucleic acids and can also be used to produce high-fidelity reverse transcriptases for RNA.

Multivalent binding is a common strategy to enhance the interactions between weak binding partners. Now, following this principle, DNA origami scaffolds have been used to arrange DNA aptamers into specific geometries and to optimize linker spacings and flexibilities, which results in artificial binding sites with very high affinities for their corresponding ligands.

Molecular rotors have been engineered within the bicyclopentane–dicarboxylate struts of a metal–organic framework—the bicyclic unit is the rotator and the carboxylate groups serve as the stator. In a zinc-based metal–organic framework, the crossed conformation of the strut–metal nodes enables fast rotation of the bicyclic moiety, but in the corresponding zirconium metal–organic framework a change in the conformation results in much slower rotation.

Many bacterial pathogens release effector enzymes belonging to the large Fic family, which modify host targets with nucleotide monophosphates. Now, recombinantly produced Fic enzymes have been equipped with synthetic thiol-reactive nucleotide derivatives to make covalent binary probes. The reaction of modified Fic enzymes with their targets permits covalent substrate capture and the structural determination of low-affinity ternary enzyme–nucleotide–substrate complexes.

The invariable core of a type II polyketide synthase has been characterized using X-ray crystallography, simulations, mutagenesis experiments and functional assays. The characterization of the ternary acyl carrier protein complexes provides a mechanistic understanding of the reactivity and could inform future engineering of this complex biosynthetic machinery.

The strength of electrostatic interactions in semiconductors strongly affects their performance in optoelectronic devices. Now, doping two-dimensional naphthalene-based lead halide perovskites with tetrachloro-1,2-benzoquinone has been shown to introduce donor–acceptor interactions within the organic network, without disrupting the inorganic sublattice. This in turn altered the energy of the materials’ electron–hole electrostatic Coulomb interactions.

Access to both enantiomers of a chiral target compound typically relies on reversing the absolute configuration of the chiral component in the reaction system that is used to make them. A time-dependent enantiodivergent synthesis is reported in which the same enantiomer of a chiral catalyst can give both enantiomers of the product, depending on the reaction time.

A general method for the enantioselective hydrocyanation of alkenes has been a long-standing synthetic challenge. Now, using a dual electrocatalytic approach that combines two synergistic redox catalytic cycles, a wide variety of chiral nitriles can be synthesized from conjugated alkenes in high enantioselectivity.

The reduction of N₂ to NH₃ is mediated in living systems by the enzyme nitrogenase and in the chemical industry by the Haber–Bosch process; both systems rely on iron-based catalysis. Now, a molecular tri(iron)bis(nitrido) complex, prepared by reduction of a bis(iron)bis(iodo) precursor under an N₂ atmosphere, has been isolated and shown to promote the formation of NH₃ from H₂.

The highly frustrated spin-1/2 kagome lattice antiferromagnet, predicted to exhibit unconventional magnetic behaviours, has remained difficult to synthesize without structural imperfections. Now, a d¹-titanium fluoride kagome lattice antiferromagnet has been prepared in which there is only one crystallographically distinct Ti³⁺ site and one type of bridging fluoride, and it is shown to be a frustrated magnet with unusual magnetic properties.

The integration of replication with metabolism represents a key step in the transition of chemistry into biology. Now, it has been shown that a self-replicator can recruit and activate two different photocatalytic cofactors, which then catalyse the synthesis of the precursors for the replicator.

Despite numerous potential applications, the development of light-responsive solid materials based on molecular photoswitches is impeded by the low efficiency of photoisomerization in the solid environment. Now a robust, solid porous material made from tetraphenylmethane and a photoswitchable overcrowded alkene exhibits nearly quantitative photoisomerization in the bulk and in photomodulation of gas uptake.

In contrast to the variety of stable carbonyl complexes of group 7–12 metals, few are known for group 3–5 metals; among those, cations have only been identified in the gas phase or by matrix isolation. Now, several unusual niobium and tantalum carbonyl compounds have been prepared as bulk crystalline compounds, including heptacarbonyl salts and the neutral ditantalum dodecacarbonyl.

The synthesis of chiral amino alcohols from simple alcohol starting materials can be achieved through a catalytic, asymmetric radical relay. Multiple catalysts work in concert to harness a H-atom transfer mechanism to enable enantio- and regioselective C–H amination by transient N-centred radicals.

Conventionally, urea is synthesized via two consecutive processes, N₂ + H₂ → NH₃ followed by NH₃ + CO₂. Now, an electrocatalyst consisting of PdCu alloy nanoparticles on TiO₂ nanosheets has been shown to directly couple N₂ and CO₂ in H₂O to produce urea under ambient conditions.