ChemSystemsChem最新文献

The creation of large information molecules may have played an essential role in the origins of life. In this study, we conducted slow freeze-thaw (F/T) experiments to test the possibility of enhanced hybridization between the complementary sticky ends attached to kilobase-sized DNA fragments at sub-nanomolar concentrations. DNA fragments of 2- and 3-kilobase pairs (kbp) with 50-base complementary sticky ends that can form 5 kbp-sized hybridization products were mixed. While simple incubation provided little hybridization product, significantly effective hybridization was observed after freezing and thawing at a controlled time rate (<0.3 K min⁻¹), even with small DNA concentrations (<1 nM). Furthermore, slow thawing had a more effect on hybridization than slow freezing. The reaction efficiency was reduced by rapid thawing instead of slow thawing, suggesting that the eutectic phase concentration played an important role in hybridization. A slow F/T cycle was effective even for the hybridization reaction between two 10 kbp DNA fragments, which yielded a 20 kbp product at sub-nanomolar concentrations. Repeating the slow F/T cycle significantly improved the reaction efficiency. The possible role of the F/T cycles in early Earth environments is discussed here.

Cells are highly functional and complex molecular systems. Artificially creating such systems remains a challenge, which has been extensively studied in various research fields, including synthetic biology and molecular robotics. DNA nanotechnology is a powerful tool for bottom-up engineering for constructing functional nanostructures or chemical reaction networks which can be utilized as components for artificial molecular systems. Encapsulation of these components into a giant unilamellar vesicle (GUV) composed of a lipid bilayer, the base structure of the cellular membrane, results in a functional cell-sized structure that partially mimics some cellular functions. This review discusses the studies contributing to the construction of GUV-based artificial molecular systems based on DNA nanotechnology. Molecular transport and signal transduction through lipid membranes are essential to uptake molecules from the environment and respond to stimuli. Membrane shaping relates to various functions, including motility and signaling. A chemical reaction network is required to autonomously regulate the system‘s functions. This review describes the functions realized using DNA nanostructures and DNA reaction networks. Given the designability and programmability of DNA nanotechnology, it may be possible that the functionality of artificial molecular systems could be comparable to or even surpass that of natural molecular systems.

Biological translation is a universal process taking place in the ribosome. It involves the synthesis of a protein with a particular sequence from the information encoded in a messenger RNA and the amino acids carried by transfer RNAs with the assistance of specific enzymes. However, the origin of translation in the prebiotic world and, thus, in the absence of enzymes is difficult to envisage. Past and recent studies proposed different prebiotic models, following top-down and bottom-up approaches, for the origin and evolution of a primitive ribosome. The bottom-up models made use of distinct covalent linkages to connect RNA strands with amino acids and peptides. In this review, I focus on the covalent linkages used in these prebiotic models: acyl phosphate mixed anhydrides, phosphoramidates and ureas. I describe their syntheses under prebiotically plausible reaction conditions, as well as include their main conventional preparation methods. I also comment on their properties and chemical stabilities in aqueous solution. Finally, I examine the functions of the described covalent linkages in prebiotic processes involving RNA-templated amino acid transfer and peptide synthesis.

Hydrothermal vents maintain far-from equilibrium conditions that may have provided the necessary settings for the origin of life. To understand reactions under these physicochemical conditions, scientists have turned to the classic demonstration experiment, chemical gardens. The self-organization of precipitate tubes separates high and low pH environments similarly to the naturally occurring geological structures. Here, we report calcium-based chemical gardens forming in solutions containing anions of silicate, carbonate, or a mixture of the two in 100 °C and 23 °C environments. Under high temperature conditions, chemical gardens tend to have faster average growth velocities and form taller structures. We measure the composition of the precipitate tubes using Fourier transform infrared spectroscopy and find the formation of all polymorphs of calcium carbonate along with calcium silicates.

The front cover artwork is provided by the Lerch group at the Stratingh Institute for Chemistry at the University of Groningen, The Netherlands. The cover illustrates a robot communicating with surrounding entities using various (chemical) signals. Not all communication and signal processing are successful, hence the slight confusion on the robot′s face. The cover alludes to the breadth of and future challenges for chemical communication within autonomous materials and robots. Cover design by Dr. Kaja Sitkowska. Read the full text of the Concept at 10.1002/syst.202400005.

The intricate interplay between self-assembly and phase separation orchestrates biomolecular organization inside cells, thereby dictating the formation of vital structures such as protein assemblies and membraneless organelles (MLOs). However, in the context of supramolecular polymerization, these fundamental processes have traditionally been studied separately. This study reevaluates the supramolecular polymerization process to unveil the presence of phase-separated droplet state. Utilizing the well-studied benzene-1,3,5-tricarboxamide (BTA) supramolecular motif, we explore its thermally driven liquid-liquid phase separation (LLPS). Thermodynamic and kinetic analysis, employing temperature-dependent spectroscopic and microscopic techniques, elucidates the distinct BTA states and their evolution towards the thermodynamic fiber state. This research sheds light on the existence of hidden phases of supramolecular monomers, emphasizing the delicate balance of non-covalent interactions among monomers and with solvents in governing self-assembly vs. phase separation. This is particularly important in comprehending phase separation in the biological realm such as in MLOs, and for applications such as condensate-modifying therapeutics.

The Front Cover illustrates a robot communicating with surrounding entities using various (chemical) signals. Not all communication and signal processing is successful, hence the slight confusion on the robot′s face. The cover alludes to the breadth of and future challenges for chemical communication within autonomous materials and robots. Cover design by Dr. Kaja Sitkowska. More information can be found in the Concept by Michael M. Lerch and co-workers.

The Cover Feature shows a Maxwell's Demon opening a trapdoor in a lipid-bilayer membrane to allow ions to move in one direction but not the other. This Concept underpins ratchet mechanisms, which have been used to develop small-molecule machines, and might soon enable the construction of artificial transmembrane pumps. More information can be found in the Concept by Stefan Borsley.

At the earliest development of prebiotic chemistry, bacterial cells were primarily viewed as “bags of molecules.” This longstanding viewpoint shaped and biased early research about life's origins, setting an initial target when considering the path from prebiotic chemistry to modern life. The two fields of systems chemistry and bacterial cell biology seem like oil and water, but each brings their own perspectives and methods to consider “what is life?”. Here, we review the most recent discoveries in bacterial cell biology, focusing on biomolecular condensates to consider how they may impact our thinking of matter-to-life transitions. The presence of condensate compartments in the bacterial domain of life strengthens the hypothesis that condensates play roles in coordinating chemical systems in life's origins. Bacterial condensates have been shown to enhance enzymatic reactions, tune substrate specificity, and be responsive to environmental conditions and metabolites. Systems chemistry studies have further illuminated the unique chemical environment within condensates and strategies for logically tying chemical processes to the formation and dissolution of condensates. We consider the potential of biomolecular condensates to provide “incubator spaces” where new chemistries can develop and examine future challenges regarding the capability of condensates to yield emergent chemical systems capable of selection.