Robustness in bacterial chemotaxis
Robustness in bacterial chemotaxis
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DOI：
10.1038/16483
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发表时间：
1999-01-14
期刊：
影响因子：
64.8
通讯作者：
Leibler, S
中科院分区：
文献类型：
--
作者：
Alon, U;Surette, MG;Leibler, S
相互作用的蛋白质网络策划了活细胞对各种外部刺激的反应（1），但是这些蛋白质网络对它们的生化参数的变化的功能有多敏感？一种可能性是聊天以实现适当的功能，需要精确调整反应速率常数和酶浓度，并且与这些“微调”值的任何偏差都会破坏网络的性能。另一种可能性是，生化网络的关键特性是强大的（2）；也就是说，它们对生化参数的精确值不敏感。在这里，我们在使用大肠杆菌的趋化性的实验中解决了这个问题，这是特征最佳的感觉系统之一（3,4）。我们专注于对吸引力信号的响应和适应性如何随趋化性网络组分的细胞内浓度的系统变化而变化。我们发现，某些特性（例如稳态行为和适应时间）在响应不同的蛋白质浓度时显示出很强的变化。相比之下，适应的精度是稳健的，并且不会随蛋白质浓度而变化。这与最近提出的用于精确适应的分子机制是一致的，鲁棒性是网络结构的直接结果（2）。
Networks of interacting proteins orchestrate the responses of living cells to a variety of external stimuli(1), but how sensitive is the functioning of these protein networks to variations in their biochemical parameters? One possibility is chat to achieve appropriate function, the reaction rate constants and enzyme concentrations need to be adjusted in a precise manner, and any deviation from these 'fine-tuned' values ruins the network's performance. An alternative possibility is that key properties of biochemical networks are robust(2); that is, they are insensitive to the precise values of the biochemical parameters. Here we address this issue in experiments using chemotaxis of Escherichia coli, one of the best-characterized sensory systems(3,4). We focus on how response and adaptation to attractant signals vary with systematic changes in the intracellular concentration of the components of the chemotaxis network. We find that some properties, such as steady-state behaviour and adaptation time, show strong variations in response to varying protein concentrations. In contrast, the precision of adaptation is robust and does not vary with the protein concentrations. This is consistent with a recently proposed molecular mechanism for exact adaptation, where robustness is a direct consequence of the network's architecture(2).