ChemSystemsChem最新文献

Silicate glasses are ubiquitous on terrestrial planets wherever molten rock – generated by volcanism or impacts – is quenched by air or water. Hence, they provided ready and abundant reactive solid surfaces for prebiotic chemistry on the early Earth. Here, we show that rock glass composition determines basicity, which in turn modulates the outcome of prebiotic synthetic processes such as the polymerization of 3’, 5’ cyclic guanosine monophosphate.

The Front Cover depicts a workflow for the supramolecular assembly-disassembly cycle of peptidic monomers bearing π-conjugated units. Through a carbodiimide-fueled approach, transformation of the peptide moieties instructs the monomers to self-assemble, yet still be responsive to thermal-assisted and hydrolysis-induced disassembly. Cover design by ScienceBrush. More information can be found in the Research Article by Herdeline Ann M. Ardoña and co-workers.

The front cover artwork is provided by Herdeline Ardoña and co-workers at UC Irvine and BioPACIFIC MIP. The image illustrates a workflow for supramolecular assembly and disassembly processes accessed through a carbodiimide-fueled approach that instructs the self-assembly and hydrolysis-induced disassembly of peptides bearing optoelectronically active units. Read the full text of the Research Article at 10.1002/syst.202300003.

Modern cells rely on highly evolved protein networks to accomplish essential life functions, including the inheritance of information from parents to their offspring. In the absence of these sophisticated molecular machineries, alternatives were required for primitive protocells to proliferate and disseminate genetic material. Recurring environmental constraints on ancient earth, such as temperature cycles, are considered as prebiotically plausible driving forces capable of shuffling of protocellular contents, thereby boosting compositional complexity. Using confocal fluorescence microscopy, we show that temperature oscillations such as freezing-thawing (FT) cycles promote efficient content mixing between giant unilamellar vesicles (GUVs) as model protocells. We shed light on the underlying exchange mechanism and demonstrate that transient periods of destabilized membranes enable the diffusion of cargo molecules across vesicle membranes. Furthermore, we determine essential parameters, such as membrane composition, and quantify their impact on the lateral transfer efficiency. Our work outlines a simple scenario revolving around inter-protocellular communication environmentally driven by periodic freezing and melting of water.

The front cover artwork is provided by Guido Panzarasa (ETH Zürich). The image shows an artistic impression of the autonomous, time-programmable temperature increase alongside acid generation in the chlorate-sulfite-gluconolactone reaction network. Read the full text of the Research Article at 10.1002/syst.202200042.

The Front Cover represents an artist impression of the autonomous, time-programmable temperature increase alongside acid generation in the chlorate-sulfite-gluconolactone reaction network. The reaction mixture, an aqueous solution of chlorate, sulfite and δ-gluconolactone, is contained in a beaker. The blue color suggests that the pH is basic, and the thermometer indicates that the mixture is at room temperature. The clock shows the time at which the reactants have been mixed. The hydrolysis of δ-gluconolactone triggers the acid-autocatalyzed exothermic chlorate-sulfite reaction. As a result, after some time the content of the beaker has become highly acidic (red color) and hot (vapors, and thermometer indicating a higher temperature). More information can be found in the Research Article by Ronny Kürsteiner and Guido Panzarasa .

Carbohydrates play a number of structural, functional, and metabolic roles in underpinning natural life processes, acting in states of both health and disease. Given this importance, over millions of years of evolution, living systems have developed an ability to recognize and bind carbohydrates, achieving remarkable recognition affinity and specificity in spite of the often hydrophilic and ubiquitous character of carbohydrate targets. In recent years, bio-inspired synthetic receptors have been developed to bind carbohydrates, with examples of (pseudo)temple-shaped receptors, flexible receptors, and dynamic-covalent/coordinative receptors reported. Certain of these have even demonstrated promising results, for example in binding glucose or exhibiting antiviral and antibiotic function. Accordingly, and in spite of remaining challenges, the development of synthetic receptors for carbohydrate recognition holds great promise to combat some of the most urgent problems facing our world today.

The de novo synthesis and self-assembly of molecules to establish the framework of living systems is a key target in the field of systems chemistry. The construction of synthetic cellular systems from scratch is one important such route to achieve this goal. This Special Collection on Protocells and Prebiotic Systems, guest edited by Dora Tang and Avinash J. Patil, showcases some of the most exciting work done in this field today. (D.Tang photograph copyright MPI-CBG).

Peptides naturally have stimuli-adaptive structural conformations that are advantageous for endowing synthetic materials with dynamic functionalities. Here, we report a carbodiimide-based approach, combined with electrostatic modulation, to instruct π-conjugated peptides to self-assemble and be responsive to thermal disassembly cues upon consumption of the assembly trigger. Quaterthiophene-functionalized peptides are utilized as a model system herein to study the formation of nanostructures at non-equilibrium states. Peptides were designed to have aspartic acid at the termini to allow intramolecular anhydride formation upon adding carbodiimide, which consequentially reduces the electrostatic repulsion and facilitates assembly. We show that the carbodiimide-fueled assembly and subsequent thermally assisted disassembly can be modulated by the net charge of the peptidic monomers, suggesting an assembly mechanism that can be encoded by sequence design. This carbodiimide-based approach for the assembly of designer π-conjugated systems offers a unique opportunity to develop bioelectronic supramolecular materials with controllable formation of dynamic and stimuli-responsive structures.

The Front Cover depicts an hourglass and suggests a pH variation over time. The temporal variation of pH caused by hydrogen or hydroxide ion autocatalytic reactions provides a convenient way to control the state or drive the mechanical motion of coupled pH-sensitive physicochemical systems. More information can be found in the Review by Brigitta Dúzs, István Lagzi and István Szalai.