Protocell models

After more than 20 years, Walde et al. (1994) returned in a way to coacervate experiments, although using other methods. Walde (from the Luisi group) repeated nucleotide polymerisation of ADP to give polyadenylic acid, catalysed by polynucleotide phosphorylase (PNPase). But instead of Oparin s coacervates, the Zurich group used micelles and self-forming vesicles. They were able to demonstrate that enzyme-catalysed reactions can take place in these molecular structures, which can thus serve as protocell models. Two different supramolecular systems were used ... 

The favourable properties which mark out vesicles as protocell models were confirmed by computer simulation (Pohorill and Wilson, 1995). These researchers studied the molecular dynamics of simple membrane/water boundary layers the bilayer surface fluctuated in time and space. The model membrane consisted of glycerine-1-monooleate defects were present which allowed ion transport to occur, whereby negative ions passed through the bilayer more easily than positive ions. The membrane-water boundary layer should be particularly suited to reactions which are accelerated by heterogeneous catalysis. Thus, the authors believe that these vesicles fulfil almost all the conditions required for the first protocells on earth ... 

From Simple Amphiphiles to Protocell Models Volume Editor Walde, P. 

Recursiveness of Production in an Intermingled Hypercycle Network. Next, a protocell model consisting of a variety of mutually catalyzing molecular species is investigated. When the numbers of molecules in a cell is not too small and the number of possible species is not too large in a cell, recursive production of a cell is achieved. This recursive production state consists of 5-12... 

Carletti, T., Serra, R., Villani, M., Poli, I., Filisetti, A. Sufficient conditions for emergent synchronization in protocell models. J. Theor. Biol. 254, 741-751 (2008)... 

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