Physical autocatalysis driven by a bond-forming thiol–ene reaction

Abstract

Autocatalysis has been extensively studied because it is central to the propagation of living systems. Chemical systems which self-reproduce like living cells would offer insight into principles underlying biology and its emergence from inanimate matter. Protocellular models feature a surfactant boundary, providing compartmentalization in the form of a micelle or vesicle and any model of the emergence of cellular life must account for the appearance, and evolution of, such boundaries. Here, we describe an autocatalytic system where two relatively simple components combine to form a more complex product. The reaction products aggregate into micelles that catalyse molecular self-reproduction. Study of the reaction kinetics and aggregation behaviour suggests a mechanism involving micelle-mediated physical autocatalysis and led to the rational design of a second-generation system. These reactions are driven by irreversible bond formation and provide a working model for the autocatalytic formation of protocells from the coupling of two simple molecular components.

Visualization of the spontaneous emergence of a complex, dynamic, and autocatalytic system

“…Conversely, if the binding arises from reactivity at a distant interface, or from a homogeneous reaction in the aqueous phase, the rate of binding should be independent of the distance from the observed interface. As such, the quantification of this correlation supports the proposed mode of reactivity, providing spatial information that would be difficult to obtain by other methods (16).…”

“…Compound 3 is an analog of a physical autocatalyst that we previously characterized (16). At present we are unable to reliably detect the smaller micelles of the earlier system using iSCAT, and so compound 3, bearing a longer hydrophobic tail, was selected as it forms larger micelles (R H ∼ 3 nm, Figs.…”

La biología sintética como desafío para comprender la autonomía de lo vivo

“…Algunos grupos de química orgánica y bioquímica están retomando esta línea de trabajo en los últimos años y logrando resultados de gran interés, utilizando ingredientes sintéticos, alternativos a los de la biología conocida. Por ejemplo, el grupo de Fletcher [Bissette et al 2014], ha dado con un sistema reactivo (enmarcado en la química de los tioles) que conduce a la producción autocatalítica de micelas y vesículas mediante la formación de un enlace (no a través de un proceso de hidrólisis, como en el caso de Luisi anteriormente descrito). De nuevo, pasado un tiempo en fase lag (fase estacionaria) y coincidiendo con el alcance de la cac (concentración crítica de agregación) del surfactante producido, se observa un incremento exponencial del rendimiento de la reacción.…”

Templated Self‐Replication in Biomimetic Systems

“…[2] There are many examples of bioinspired autocatalytic systems capable of physical reproduction, such as self-reproducing micelles and aggregates, [3][4][5][6] vesicles, [7][8][9][10][11][12] or number of genes required for protein synthesis and minimal metabolism. [2] There are many examples of bioinspired autocatalytic systems capable of physical reproduction, such as self-reproducing micelles and aggregates, [3][4][5][6] vesicles, [7][8][9][10][11][12] or number of genes required for protein synthesis and minimal metabolism.…”

“…At the most basic level, self-replication can be defined as a special type of autocatalysis in which the replicative unit has specificity, i.e., it recognizes the necessary building blocks necessary for its own formation and catalyzes the formation of a copy of itself. [2] There are many examples of bioinspired autocatalytic systems capable of physical reproduction, such as self-reproducing micelles and aggregates, [3][4][5][6] vesicles, [7][8][9][10][11][12] or number of genes required for protein synthesis and minimal metabolism. Thus, most protein-based replication systems currently resemble viral parasites as they rely on the presence of externally supplied translation machinery.…”