Articles in 2018

The common form of salt has a 1:1 ratio of Na⁺ and Cl⁻; however, species that deviate from this can be found under extreme conditions, such as high pressure. Now, as a result of cation–π interactions that promote ion–surface adsorption, Na₂Cl and Na₃Cl have been observed as two-dimensional crystals on graphene at ambient conditions.

Cholesterol embedded in lipid membranes strongly promotes the aggregation of Aβ42 that is associated with Alzheimer's disease. Now, a kinetic analysis has shown that the mechanism of action responsible for this effect involves the introduction of a heterogeneous nucleation pathway that enhances the primary nucleation rate of Aβ42 aggregation by up to 20-fold.

Multi-electron redox reactions are kinetically sluggish; however, plasmonic nanoparticles have shown promise as multi-electron reduction catalysts. Now, the principles that govern the harvesting of multiple electron–hole pairs from plasmonically excited gold nanoparticle photocatalysts are elucidated, providing a general foundation for the plasmonic catalysis of challenging multi-electron, multi-proton chemistry, such as N₂ fixation and CO₂ reduction.

Controlled motion in mechanically interlocked molecules, such as a macrocycle moving back and forth along the axle of a rotaxane, forms the basis of complex functions in molecular machinery. Now, ring-through-ring shuttling has been achieved using two macrocycles that switch position between two anchoring sites, which involves the smaller ring passing through the larger one.

Biological systems are made up of complex networks that can respond to stimuli and function across relatively long distances in molecular terms. Now, it has been shown that a local disruption (the isomerization of just a single azobenzene unit) at the interface of supramolecular glassy polymersomes can immediately spread through over 500 bonds, significantly changing membrane permeability and enabling controllable release of guest molecules.

Living systems rely on externally tuneable and stimuli-responsive conformational changes of proteins and protein assemblies for a wide range of essential functions. A combination of experimental and computational analyses has now enabled the fabrication of a rationally designed, synthetic, stimuli-responsive protein assembly through modulation of its free-energy landscape.

Glycosylation is an attractive strategy to functionalize natural products and peptides for biomedical use, but non-enzymatic approaches usually require organic solvent and protecting groups. Now, an aqueous phenolic O-glycosylation reaction that uses glycosyl fluoride donors and a calcium salt has been developed for a wide range of substrates, including complex unprotected peptides.

Gene expression profiling remains cost-prohibitive and challenging to implement in a clinical setting. Now, a molecular computation strategy for classifying complex gene expression signatures has been developed. Classification occurs through a series of molecular interactions between RNA inputs and engineered DNA probes designed to implement a relevant linear classification model.

Amino acids have now been used as chemical inputs to provide control over self-assembly in semiconducting structures. This approach enables temporal control over the formation of nanostructures and consequently control over their transient electronic conductivity.

Crosslinking within peptides containing two pairs of cysteines to form chemical bridges has now been shown to provide rapid access to thousands of different macrocyclic scaffolds in libraries that are easy to synthesize, screen and decode. Applying this strategy to phage-encoded libraries yielded binders with remarkable affinities despite the small molecular mass.

A manganese phthalocyanine has been shown to catalyse intermolecular C–H amination reactions—proceeding through an electrophilic metallonitrene intermediate—with high levels of reactivity and site selectivity. Demonstrating good tolerance for tertiary amine, pyridine and benzimidazole moieties, nitrogen functionality can be selectively installed at electron-rich, sterically exposed benzylic sites in bioactive molecules.

Calcium-ion batteries are potentially attractive alternatives to lithium-ion batteries, but remain largely unexplored because of low performance. A reversible calcium alloying/de-alloying reaction with the tin anode has now been coupled with the intercalation/de-intercalation of hexafluorophosphate in the graphite cathode to enable a calcium-ion battery that operates stably at room temperature.

Our understanding of reaction dynamics has developed as more accurate measurements of product state-resolved angular distributions have become available. Now, fast forward-scattering oscillations in the product angular distribution of the benchmark chemical reaction H + HD → H₂ + D have been observed and are in excellent agreement with quantum-mechanical dynamics calculations.

I-motif DNA structures are thought to form in cytosine-rich regions of the genome and to have regulatory functions; however, in vivo evidence for the existence of such structures has so far remained elusive. Now an engineered antibody that is selective for i-motif structures has been developed and used to detect i-motifs in the nuclei of human cells.

Adrian Dingle relates how one ‘element’ that fell off the periodic table was eventually replaced by two.

Proteins are attractive material building blocks, yet their intrinsic functionality has remained largely untapped. Now, a protein-based material that exhibits controllable self-assembling behaviour has been prepared in a one-pot synthesis by simultaneous use of recombinant expression and post-translational modification.

Bruce C. Gibb discusses the biochemistry behind the sensory experiences associated with eating chillies and the lesser-known tingle-inducing ‘sanshools’.

The M-cluster in the active site of nitrogenase is derived from an 8Fe core assembled via coupling and rearrangement of two [Fe₄S₄] clusters concomitant with the insertion of an interstitial carbon and a ninth sulfur. Now, by combining synthetic [Fe₄S₄] clusters and assembly with a protein template, it has been shown that sulfite gives rise to the ninth sulfur that is inserted into the nitrogenase cofactor after the radical SAM-dependent carbide insertion and cofactor core rearrangement.