Volume 14 Issue 11, November 2022

Sit back and settle in for a tour of the chemical analysis instruments aboard the James Webb Space Telescope and the techniques being used to explore the planets beyond our Solar System.

DNA nanotechnology and synthetic biology both aim to expand the range of dynamic behaviours exhibited by rationally programmed biomolecules. Now, the programmability of synthetic transcriptional circuits has been improved to enable synthesis of dynamic biomolecular circuits with unmatched complexity.

Noyori-type catalysts and inorganic bases are frequently used together for homogeneous hydrogenation, but key intermediates have not yet been isolated. Now, the structure and reactivity of a long-postulated intermediate — the alkali metal amidate complex — have been reported through experimental and computational studies.

Hydrogen, which possesses the highest gravimetric energy density of any energy carrier, is attractive for both mobile and stationary power, but its low volumetric energy density poses major storage and transport challenges. This Perspective delineates potential use cases and defines the challenges facing the development of materials for efficient hydrogen storage.

Synthetic chemical networks with far-from-equilibrium dynamics akin to genetic regulatory networks in living cells could precisely regulate the kinetics of chemical synthesis or self-assembly. Now standardized excitable chemical regulatory elements, termed genelets, that enable predictive bottom-up construction of in vitro networks with designed temporal and multistable behaviour have been developed.

Noyori-type hydrogenation catalysts consist of an N–H moiety coordinated to a metal centre. Now, a metal-hydride amidate complex (HMn–NLi) has been isolated and found to have superior reactivity and catalytic performance compared with the corresponding HMn–NH complex, highlighting the superiority of M/NM′ bifunctional catalysis over the classic M/NH bifunctional catalysis for hydrogenation reactions.

Cyclic polymers are topologically interesting and envisioned as a lubricant material, but methods for the scalable synthesis of pure cyclic polymers are currently elusive. Now, a scalable process has been developed by leveraging heterogeneity of the catalysts with the help of compartmentalized custom glassware, namely, a cyclic polymer dispenser.

Inverse vulcanization (IV) generates sulfur-rich functional polymers from elemental sulfur and organic crosslinkers, but the harsh reaction conditions required limit the scope of suitable crosslinkers. Now, a photoinduced IV has been shown to proceed at ambient temperatures, enabling the use of volatile and gaseous alkenes and alkynes as crosslinkers and broadening the range of products.

A method has been developed to identify RNA transcript isoforms at the single-molecule level using solid-state nanopore microscopy. In this method, target RNA is refolded into RNA identifiers with designed sets of complementary DNA strands. Each reshaped molecule carries a unique sequence of structural (pseudo)colours that enables identification and quantification using solid-state nanopore microscopy.

The reduction of nitrite (NO₂⁻) to nitric oxide (NO), relevant to the biogeochemical nitrogen cycle as well as radioactive waste, typically occurs at redox-active metal centres. Now, a Lewis acid-capped nitrite has been reduced to the nitrite dianion (NO₂²⁻), a nitrogen-centred radical that connects three redox levels in the global nitrogen cycle through NO₂⁻, NO and N₂O.

General synthetic methods to access pleuromutilin antibiotics are limited due to their complex carbocyclic skeleton. Now, a synthetic platform has been developed to access structurally diverse pleuromutilins with variations at the quaternary C12 position and hydrindanone cores. Seventeen structurally distinct derivatives were prepared and evaluated against a panel of Gram-positive and -negative bacteria.

Proteins rich in phenylalanine-glycine (FG) repeats can phase separate through FG–FG interactions. The molecular interactions of an important FG-repeat protein, nucleoporin 98, have now been studied in liquid-like transient and amyloid-like cohesive states. These interactions underlie the behaviour of FG-repeat proteins and their function in physiological and pathological cell activities.

The principal mid-visible light-harvesting system in cyanobacteria is the phycobilisome. Now, using broadband multidimensional spectroscopy, delocalized vibronic excitations and sub-picosecond excitation transfer pathways have been observed in the rods of intact phycobilisomes. An observed kinetic bottleneck in the phycobilisome’s core arises from the intramolecular charge-transfer character of the bilin chromophores, enabling photoregulatory processes to operate on the >10-ps timescale.

Oligonucleotide catalysts such as ribozymes and DNAzymes can cleave RNA efficiently and specifically but are typically dependent on high concentrations of divalent cations, limiting their biological applications. A modular XNAzyme catalyst composed of 2′-deoxy-2′-fluoro-β-d-arabino nucleic acid (FANA) has now been developed that can cleave long (>5 kb), highly structured mRNAs under physiological conditions and enables allele-specific catalytic RNA knockdown inside cells.

The rapid assembly of complex scaffolds in a single step from simple precursors would be an ideal reaction in terms of efficiency and sustainability. Now, the single-step construction of alkaloid-like frameworks from three dynamically assembled precursors has been reported. Using a dual-catalytic system, the transformation involves a hydride shuttle process initiated by a hydride donation event.

Automated systems, nowadays more commonly used in laboratory settings, are typically fixed to a narrow set of reactions and used within a complex laboratory environment. Now, a portable platform has been developed for the on-demand and on-site multistep synthesis of organic molecules, oligonucleotides and oligopeptides mapped into reactionware systems.

In some cases, hydrogen adsorption close to its boiling temperature shows unusually high monolayer capacities, but the microscopic nature of this adsorbate phase is not well understood. Now, H₂ adsorbed on a well-ordered mesoporous silica surface has been shown to form a 2D monolayer with very short H₂···H₂ intermolecular distances and a density more than twice that of bulk-solid H_2.

The biosynthesis of fuscimiditide, a ribosomally synthesized post-translationally modified peptide, has now been reported. Heterologous expression and analysis of fuscimiditide showed it contained two side-chain–side-chain ester linkages and an aspartimide in its backbone. The aspartimide moiety is unexpectedly stable, suggesting this structure is the intended natural product.

Anna Ampaw reflects on the effects of antifreeze proteins, from Arctic fish to fruity ice creams.