Mais um modelo sobre a origem da vida: emergência espontânea de polímeros de codificação de informação autocatalítica

terça-feira, julho 28, 2015

Spontaneous emergence of autocatalytic information-coding polymers

Alexei V. Tkachenko 1,a) and Sergei Maslov 2,3,b)

1 Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA

2 Biological, Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, New York 11973, USA

3 Department of Bioengineering, University of Illinois at Urbana-Champaign, 1270 Digital Computer Laboratory, MC-278, Urbana, Illinois 61801, USA

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J. Chem. Phys. 143, 045102 (2015);


Self-replicating systems based on information-coding polymers are of crucial importance in biology. They also recently emerged as a paradigm in material design on nano- and micro-scales. We present a general theoretical and numerical analysis of the problem of spontaneous emergence of autocatalysis for heteropolymers capable of template-assisted ligation driven by cyclic changes in the environment. Our central result is the existence of the first order transition between the regime dominated by free monomers and that with a self-sustaining population of sufficiently long chains. We provide a simple, mathematically tractable model supported by numerical simulations, which predicts the distribution of chain lengths and the onset of autocatalysis in terms of the overall monomer concentration and two fundamental rate constants. Another key result of our study is the emergence of the kinetically limited optimal overlap length between a template and each of its two substrates. The template-assisted ligation allows for heritable transmission of the information encoded in chain sequences thus opening up the possibility of long-term memory and evolvability in such systems.