ChemSystemsChem最新文献

The RNA World theory for the origin of life requires polymers to be generated initially by abiotic reactions. Experiments have studied polymerization of 5′-monophosphates, 2′,3′-cyclic phosphates, and 5′-triphosphates. We consider theoretical models of polymerization in solution illustrating the differences between these cases. We consider (i) a basic model where all monomers undergo reversible joining and breaking; (ii) a model where 2′,3′-cyclic phosphates can join, and breaking regenerates the cyclic phosphate; (iii) a model where 5′-triphosphates can join irreversibly, in addition to the joining and breaking of 2′,3′-cyclic phosphates. In cases (i) and (ii) there is an equilibrium steady state with balance between making and breaking bonds. In case (iii) there is a circular reaction flux in which monomers are activated by an external phosphate source, activated monomers form polymers, and polymers break to release non-activated monomers. The mean length can be calculated as a function of concentration. In case (iii), the mean length switches from a low-concentration regime controlled by the 5′-triphosphates to a high-concentration regime controlled by the 2′,3′-cyclic phosphates. The circular reaction flux is reminiscent of a metabolism. If formation of 5’-triphosphates was already in place for RNA synthesis, ATP could subsequently been coopted for metabolism.

In recent years, there has been a growing interest in multi-compartment systems as a means of developing materials that mimic the structure and function of biological cells. These hierarchical systems, including artificial cells and cell-like reactors, can efficiently perform biochemical tasks by exploiting compartmentalization inspired by biological systems. However, the bottom-up design of cell mimics presents significant challenges due to the need for precise and efficient assembly of components. This short review examines recent advances in droplet-based microfluidics (DBM), which has emerged as a powerful technique for creating cell-like systems with multi-compartment architectures, precise composition, and biomimetic functionality. DBM has proven to be a reliable method for generating populations of cell-mimics with a compartment-in-compartment structure, some of which have adaptable properties that resemble the dynamic properties of natural cells. Notable examples will be discussed to illustrate how droplet-based microfluidics provides a versatile approach to create, manipulate, and study cell-mimics.

The Front Cover illustrates the exchange of genetic material between model protocells through cycles of freezing and thawing. Freeze-thaw cycles as prebiotic environmental driver induce a transient increase in membrane permeability enabling the lateral transfer of genetic information in a population of primitive protocells. More information can be found in the Research Article by Benedikt Peter and Petra Schwille.

The front cover artwork is provided by the Schwille group from the Max Planck Institute of Biochemistry in Martinsried. The image shows the dissemination of genetic material in a population of primitive protocells during freeze-thaw induced periods of membrane permeability. Read the full text of the Research Article at 10.1002/syst.202300008.

Building synthetic multicellular systems using non-living molecular components is a grand challenge in the field of bottom-up synthetic biology. Towards this goal, a diverse range of chemistries have been developed to provide mechanisms of intercellular communication and methods to assemble multicellular compartments. However, building bottom-up synthetic multicellular systems is still challenging because it requires the integration of intercellular reaction networks with compatible cellular compartment properties. In this study, we encapsulated cell-free expression systems (CFES) expressing two quorum sensing genetic circuits into droplet interface bilayer (DIB) synthetic cells to demonstrate bidirectional communication. We further develop a method of generating custom DIB multicellular structures by acoustic liquid handling to automatically dispense the CFES droplets and show the potential for multiplexing compartmentalized gene circuits for generating heterogeneous populations of cells. Our work provides a step towards building more complex multicellular systems with intercellular communication from the bottom-up to study and experimentally model biological multiscalar processes.

A strong revival of interest has been dedicated to peptides over the last few years, in different fields including drug discovery, biosensing and material sciences. The use of dynamic covalent chemistry has allowed the development of self-adaptative peptides or peptidomimetics, responsive to their environment. The development of methods allowing the building, screening or deconvolution of libraries of peptides is a highly active research area and dynamic combinatorial chemistry represents an innovative and underexploited method in this field. This Review gives an overview of the use of dynamic covalent chemistry as a tool to produce peptides or peptidomimetics, with particular attention to applications in dynamic combinatorial chemistry.

A three-component molecular ensemble consisting of the constitutionally dynamic cage 1, rotaxane 2 and luminophore 3 acts as a signal transducer which assimilates three input signals, i. e., Zn²⁺, H⁺, and Cu⁺, to perform individual logic operations (e. g. a 3-input NOR gate with catalytic output, 3-input AND gate with optical output) and operates as an unconventional 3-input demultiplexer.

The spontaneous emergence of function from diverse RNA sequence pools is widely considered an important transition in the origin of life. Here we show that diverse sequence pools are not a prerequisite for the emergence of function. Starting five independent selection experiments each from a single RNA seed sequence - comprising a central homopolymeric poly-A (or poly-U) segment flanked by different conserved primer binding sites - we observe transformation (continuous drift) of the seeds into low diversity sequence pools by mutation, truncation and recombination without ever reaching that of a random pool even after 24 rounds. Upon continuous error prone replication and selection for ATP binding we isolate specific ATP- or GTP-binding aptamers with low micromolar affinities. Our results have implications for early RNA evolution in the light of the high mutation rates associated with both non-enzymatic and enzymatic prebiotic RNA replication.

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.