The evolutionary dynamics of metabolic protocells.
The evolutionary dynamics of metabolic protocells.
复制标题
代谢原细胞的进化动力学。
DOI：
10.1371/journal.pcbi.1006265
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发表时间：
2018-07
影响因子：
4.3
通讯作者：
Bergman A
中科院分区：
文献类型：
--
作者：
Pechuan X;Puzio R;Bergman A
Protocell multilevel selection models have been proposed to study the evolutionary dynamics of vesicles encapsulating a set of replicating, competing and mutating sequences. The frequency of the different sequence types determines protocell survival through a fitness function. One of the defining features of these models is the genetic load generated when the protocell divides and its sequences are assorted between the offspring vesicles. However, these stochastic assortment effects disappear when the redundancy of each sequence type is sufficiently high. The fitness dependence of the vesicle with its sequence content is usually defined without considering a realistic account on how the lower level dynamics would specify the protocell fitness. Here, we present a protocell model with a fitness function determined by the output flux of a simple metabolic network with the aim of understanding how the evolution of both kinetic and topological features of metabolism would have been constrained by the particularities of the protocell evolutionary dynamics. In our model, the sequences inside the vesicle are both the carriers of information and Michaelis-Menten catalysts exhibiting saturation. We found that the saturation of the catalysts controlling the metabolic fluxes, achievable by modifying the kinetic or stoichiometric parameters, provides a mechanism to ameliorate the assortment load by increasing the redundancy of the catalytic sequences required to achieve the maximum flux. Regarding the network architecture, we conclude that combinations of parallel network motifs and bimolecular catalysts are a robust way to increase the complexity of the metabolism enclosed by the protocell. The protocell hypothesis conjectures the existence of a vesicle containing catalytic and replicating sequences as the primordial cellular organization during the early stages of the evolution of life. Mathematical models of protocells traditionally consider RNA sequences being encapsulated and having both an informational and a catalytic role in the same molecule. Because of this dual function, the protocell sequences are evolutionarily constrained. Mathematical models have been extensively used to study the evolutionary dynamics of protocells with a focus on the processes, like mutation or stochastic sequence assortment upon division, that affect the protocell information capacity in terms of the coexistence of different sequence types. Here we introduce a simple model of metabolic networks whose output determines the survival of the protocell with the aim of studying the effect of modifying the kinetic and architectural properties of the network on sequence coexistence. We find that stochastic assortment and mutation limit the architectures able to be encapsulated by the protocell with a given fraction of the population harbouring all possible sequence types.
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影响因子：
2
作者：
Hubai, Andras G.;Kun, Adam
通讯作者：
Kun, Adam
影响因子：
3.9
作者：
KACSER, H;BEEBY, R
通讯作者：
BEEBY, R
影响因子：
4
作者：
BOERLIJST, MC;HOGEWEG, P
通讯作者：
HOGEWEG, P
影响因子：
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作者：
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通讯作者：
Yomo, T
影响因子：
4.3
作者：
Boza, Gergely;Szilagyi, Andras;Szathmary, Eoers
通讯作者：
Szathmary, Eoers