Abundant indispensable redundancies in cellular metabolic networks.
Abundant indispensable redundancies in cellular metabolic networks.
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DOI：
10.1093/gbe/evp002
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发表时间：
2009-04-30
影响因子：
3.3
通讯作者：
Zhang J
中科院分区：
文献类型：
--
作者：
Wang Z;Zhang J
细胞生命是一个高度冗余的复杂系统；然而，这种冗余的进化维持仍未得到解释。利用系统生物学方法，我们推断在任何营养条件下，大肠杆菌和酵母中37 - 47%的代谢反应可以被单独去除，而不会阻碍任何生物量组分的产生。然而，这些冗余反应中的大多数被保留下来，是因为它们在不同条件下具有不同的最大效率，或者它们的缺失会立即导致适应性降低，而这种适应性降低只能通过进化中的突变、漂变和选择来恢复。其余的冗余可归因于多效性效应或近期的水平基因转移。我们发现大肠杆菌和酵母在反应的功能重要性和冗余水平之间呈现出相反的关系，这与冗余是作为对系统中重要部分的备份而被保留的推测不一致。有趣的是，这种相反的关系都可以通过一个简单的模型来重现，在该模型中生物体的自然环境频繁变化。因此，适应性备份对于解释细胞代谢网络的高度冗余既不是必要的，也不是充分的。综上所述，我们的结果有力地表明，冗余反应不是作为备份被保留的，代谢网络的遗传稳健性是一种进化的副产物。
Cellular life is a highly redundant complex system; yet, the evolutionary maintenance of the redundancy remains unexplained. Using a systems biology approach, we infer that 37–47% of metabolic reactions in Escherichia coli and yeast can be individually removed without blocking the production of any biomass component under any nutritional condition. However, the majority of these redundant reactions are preserved because they have differential maximal efficiencies at different conditions or their loss causes an immediate fitness reduction that can only be regained via mutation, drift, and selection in evolution. The remaining redundancies are attributable to pleiotropic effects or recent horizontal gene transfers. We find that E. coli and yeast exhibit opposite relationships between the functional importance and redundancy level of a reaction, which is inconsistent with the conjecture that redundancies are preserved as an adaptation to back up important parts in the system. Interestingly, the opposite relationships can both be recapitulated by a simple model in which the natural environments of the organisms change frequently. Thus, adaptive backup is neither necessary nor sufficient to explain the high redundancy of cellular metabolic networks. Taken together, our results strongly suggest that redundant reactions are not kept as backups and that the genetic robustness of metabolic networks is an evolutionary by-product.
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影响因子：
56.9
作者：
Hillenmeyer, Maureen E.;Fung, Eula;Giaever, Guri
通讯作者：
Giaever, Guri
DOI：
10.1073/pnas.91.8.2950
发表时间：
1994-04-12
影响因子：
11.1
作者：
CLARK, AG
通讯作者：
CLARK, AG
影响因子：
12.3
作者：
Blank LM;Kuepfer L;Sauer U
通讯作者：
Sauer U
影响因子：
14.8
作者：
Becker, Scott A.;Feist, Adam M.;Herrgard, Markus J.
通讯作者：
Herrgard, Markus J.
DOI：
10.1073/pnas.142314099
发表时间：
2002-07-23
影响因子：
11.1
作者：
Kandror, O;DeLeon, A;Goldberg, AL
通讯作者：
Goldberg, AL