Reviews & Analysis

The precision synthesis of cyclic polymers with ultrahigh molar mass (UHMM) and circularity is challenging. Now, a method that involves superbase-mediated living linear-chain growth followed by macromolecular cyclization triggered by protic quenching enables the on-demand production of UHMM cyclic polymers with a narrow dispersity and closed-loop chemical recyclability.

A non-radical proximity labelling platform — BAP-seq — is presented that uses subcellular-localized BS2 esterase to convert unreactive enol-based probes into highly reactive acid chlorides in situ to label nearby RNAs. When paired with click-handle-mediated enrichment and sequencing, this chemistry enables high-resolution spatial mapping of RNAs across subcellular compartments.

Ether-based electrolytes are desired for lithium metal batteries owing to their low reduction potentials; however, they suffer from low anodic stability. Strategic methylation of ether solvents is shown to extend their electrochemical stability and facilitate the formation of LiF-rich interphases, enabling high-voltage lithium metal batteries while avoiding the use of fluorinated solvents.

We developed a high-throughput, unbiased strategy for the identification of endogenous biomolecular condensates by merging cell volume compression, sucrose density gradient centrifugation and quantitative mass spectrometry. We demonstrated the performance of this strategy by identifying both global condensate proteins and those responding to specific biological processes on a proteome-wide scale.

A method for carbon isotope exchange involving a metal-catalysed metathesis reaction of in situ formed acyl chlorides is demonstrated. The platform provides access to ¹³C- or ¹⁴C-enriched carboxylic acids, including natural products and pharmaceuticals, without the need for radioactive gases, using a single carboxylic acid carbon donor.

Covalent protein conjugation facilitates the study of biological processes and the synthesis of therapeutic biomacromolecules. A method that uses vinyl thianthrenium reagents for the site-selective formation of highly reactive episulfonium species on proteins is demonstrated. These in situ-formed intermediates react with diverse nucleophiles, providing access to protein conjugates in one step without purification.

A protein-templated selection approach has been developed for the discovery of full ligands from dual-pharmacophore DNA-encoded libraries by incorporating fragment linking into the selection process. The performance of this method was demonstrated with selections against protein–protein interaction and protein–DNA interaction targets, through which potent and selective inhibitors were identified.

Dinitrogen (N₂) fixation to ammonia (NH₃) is typically challenging under mild conditions. Now, lithium hydride (LiH) is shown to mediate photodriven N₂ fixation under ambient conditions. Under ultraviolet illumination, LiH is photolysed to release H₂, leaving electrons residing in surface hydrogen vacancies, which facilitate N₂ activation and photocatalytic NH₃ synthesis.

Trans–cis photoisomerization is a fundamental photochemical reaction that is thought to proceed through an intermediate with a perpendicular conformation. However, unambiguous identification of this state has proved challenging. The combination of state-of-the-art ultrafast spectroscopy and quantum chemical calculations now provides evidence for its structural observation in stilbene photoisomerization.

Ribonucleoprotein granules are ubiquitous in living organisms with the protein and RNA components having distinct roles. In the absence of proteins, RNAs are shown to undergo phase separation upon heating. This transition is driven by desolvation entropy and ion-mediated crosslinking and is tuned by the chemical specificity of the RNA nucleobases.

To develop covalent inhibitors with high potency and low off-target effects, combinatorial approaches that search for candidates from large libraries are desired. Here, sulfur(VI) fluoride exchange (SuFEx) in vitro selection is established for the evolution of covalent aptamers from trillions of SuFEx-modified oligonucleotides. Through this technique, covalent aptamers with optimally balanced selectivity and reactivity are identified.

Aromatic oligoamide macrocycles have been developed in which the constrained backbone enforces hydrogen-bond donors to orient towards the macrocycle centre, forming a highly electropositive cavity. These macrocycles show strong binding for various anions and can partition into biomembranes to facilitate selective transmembrane anion transport.

An infrared laser-induced temperature jump provides a rapid and broadly applicable perturbation to protein dynamics. Temperature-jump crystallography was paired with time-resolved X-ray crystallography to study the dynamic enzyme lysozyme. Measurements with and without a functional inhibitor revealed different patterns in the propagation of motion throughout the enzyme.

Experimental and computational studies establish the operation of Fe(iii)-based metalloradical catalysis for the asymmetric cyclopropanation of alkenes with different classes of diazo compounds. The reaction proceeds through a stepwise radical mechanism involving α-Fe(iv)-alkyl and γ-Fe(iv)-alkyl radical intermediates. This work provides a future direction for the development of metalloradical catalysis.

Radiation damage in biological systems by radicals and low-energy electrons formed from water ionization is a consequence of ultrafast processes that follow core-level ionization of hydrated metal ions. More details of the complex pathway are now revealed from the study of aluminium-ion relaxation through sequential electron-transfer-mediated decay.

A multimodal imaging approach is developed to interrogate microorganism–semiconductor biohybrids at the single-cell and single-molecule level for light-driven CO₂ fixation. Application to lithoautotrophic bacterium Ralstonia eutropha biohybrids reveals the roles of two hydrogenases in electron transport and bioplastic formation, the magnitude of semiconductor-to-single-cell electron transport and the associated pathways.

Despite advances, understanding of the quantum state-to-state scattering dynamics between charged ions and neutral molecules at low collision energies remains limited. A high-resolution crossed-beam experiment with quantum state-selected ions prepared by laser photoionization and supporting trajectory surface-hopping calculations now provides insight into the quantum state-to-state collisional dynamics of a model charge-transfer reaction.

Challenges in the synthesis of heparan sulfate (HS) glycosaminoglycans have limited access to defined HS oligosaccharides bearing a diverse array of sulfation sequences. A concise, divergent synthetic approach now provides a library of 64 HS tetrasaccharides displaying a comprehensive set of sulfation sequences, offering insight into the elusive sulfation code of glycosaminoglycans.

Protein translation is the ultimate paradigm for sequence-defined polymer synthesis. To introduce non-canonical monomers into the genetic code of living organisms, pairs of biomolecules known as aminoacyl-tRNA synthetases (aaRSs) and transfer RNAs (tRNAs) are required. The discovery and engineering of five such pairs, that do not interfere with each other or the aaRS–tRNA pairs of a bacterial host, sets the stage for highly modified genetically encoded biopolymers.

Low-coordinate lanthanide complexes with strong magnetic anisotropy could afford high-performance single-molecule magnets (SMMs) but are challenging to synthesize. Now, through ligand design, a near-linear pseudo-two-coordinate Yb(iii) complex that exhibits slow magnetic relaxation is reported. The complex has a large total splitting of the ground-state manifold, arising from the crystal field imposed by the ligands.