School of Engineering Sciences in Chemistry, Biotechnology and Health, Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, Sweden.
Elife. 2021 Nov 1;10:e69019. doi: 10.7554/eLife.69019.
Bacteria must balance the different needs for substrate assimilation, growth functions, and resilience in order to thrive in their environment. Of all cellular macromolecules, the bacterial proteome is by far the most important resource and its size is limited. Here, we investigated how the highly versatile 'knallgas' bacterium reallocates protein resources when grown on different limiting substrates and with different growth rates. We determined protein quantity by mass spectrometry and estimated enzyme utilization by resource balance analysis modeling. We found that invests a large fraction of its proteome in functions that are hardly utilized. Of the enzymes that are utilized, many are present in excess abundance. One prominent example is the strong expression of CBB cycle genes such as Rubisco during growth on fructose. Modeling and mutant competition experiments suggest that CO-reassimilation through Rubisco does not provide a fitness benefit for heterotrophic growth, but is rather an investment in readiness for autotrophy.
细菌必须平衡基质同化、生长功能和弹性恢复等不同需求，才能在其环境中茁壮成长。在所有细胞大分子中，细菌蛋白质组迄今为止是最重要的资源，其规模是有限的。在这里，我们研究了高度多功能的“爆炸气”细菌如何在不同的限制底物和不同的生长速率下重新分配蛋白质资源。我们通过质谱法确定了蛋白质的数量，并通过资源平衡分析模型估计了酶的利用情况。我们发现，它将很大一部分蛋白质组投入到几乎不被利用的功能中。在被利用的酶中，许多酶的含量过高。一个突出的例子是，当以果糖为生长基质时，Rubisco 等 CBB 循环基因的强烈表达。模型和突变体竞争实验表明，Rubisco 介导的 CO 再同化并不能为异养生长提供适应性优势，而是为自养做好准备的一种投资。
