Transmission of photo-catalytic function in a self-replicating chemical system: in situ amphiphile production over two protocell generations

Abstract

Glass microsphere supported protocells were built to investigate the transmission of catalytic function during replication. The chemical system's replication was driven through in situ amphiphile production that resulted in the formation of free bilayers, the system's second "generation". It was demonstrated that both generations, once separated, still exhibited the ability to convert amphiphile precursors. This result shows that transmission of function in chemical systems is possible during self-replication.

Generating minimal living systems from non-living materials and increasing their evolutionary abilities

“…This oligomer can only then, and in the presence of a template, be ligated with another oligomer [19]. Further, we have demonstrated that DNA conjugated bola-amphiphile can be anchored to a fatty acid vesicle [20], demonstrating how information and container can be linked as well as how metabolically driven (Ru(bpy) 3 photosensitizer) self-replicating vesicles indeed divide through budding and thus inherit anchored metabolic molecules [21,22] (figure 3).…”

“…These mixed amphiphile systems often tend to form more stable structures, having different biophysical properties (e.g. permeability), than those observed when only one single amphiphile type is used [21,22]. We have even demonstrated that a single-chain amphiphile with an acid head group flanking each side of the hydrocarbon chain (hexadecanedioic acid, a bola-amphiphile) can form vesicles according to various preparation methods [66].…”

Chemical systems, chemical contiguity and the emergence of life

“…The propensity of amphiphiles to integrate pre-existing structures [ 94 – 95 ] has been experimentally exploited either by adding more amphiphiles at a pace that prevents the de novo formation of novel structures [ 17 ] or by adding amphiphile precursors that had to be converted within the structures into amphiphilic molecules themselves [ 83 , 96 – 97 ]. However, two features that are potentially detrimental to the reproduction of functional protocells were recognized: a) Even in the presence of a metabolic model, the reproduction of the internal “metabolic” network and compartment boundaries must be linked to avoid the production of non-functional systems [ 98 ]; b) the spontaneous division of the growing systems was found difficult to achieve in a predictable way.…”

The origin of life and the potential role of soaps

“…This is especially true for the reaction network encapsulated in the aqueous lumen as replication can occur in a disjointed fashion. Recently, the transmission of a simple catalytic function (the photochemical production of amphiphiles) [11] has been carried out using glass microsphere supported decanoic acid bilayers with tethered ruthenium com-plexes (Figure 3, 1). In such a set-up, the original protocell (containing glass microspheres) and any newly formed 2 nd protocell generation (vesicles lacking microspheres) could be easily separated by density differential.…”