CONTROL ANALYSIS OF THE DEPENDENCE OF ESCHERICHIA-COLI PHYSIOLOGY ON THE H+-ATPASE
CONTROL ANALYSIS OF THE DEPENDENCE OF ESCHERICHIA-COLI PHYSIOLOGY ON THE H+-ATPASE
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DOI：
10.1073/pnas.90.17.8068
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发表时间：
1993-09-01
影响因子：
11.1
通讯作者：
WESTERHOFF, HV
中科院分区：
文献类型：
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作者：
JENSEN, PR;MICHELSEN, O;WESTERHOFF, HV
H ~+-ATP酶在大肠杆菌自由能传递中起着重要作用，因此在大肠杆菌中也起着重要作用。大肠杆菌生理学我们在这里调查的程度，这种酶也控制的生长速度，生长产量和呼吸速率的E。杆菌我们调节atp操纵子的表达并确定对所述性质的影响。当根据控制系数进行定量时，我们发现，在基本培养基中在葡萄糖上生长的野生型细胞中，该关键酶（H+-ATP酶）几乎不控制生长速率（C的绝对值< 0.01），对生长产量（C = 0.15）有较小的阳性对照，对呼吸速率（C = -0.25）有较小但阴性的对照。酶对碳和自由能底物消耗速率的控制是负的（C = -0.15）。我们还研究了控制系数本身如何随atp操纵子的表达而变化。随着atp操纵子表达水平的降低，H+-ATP酶对生长速率和生长产量的控制略有增加;当atp操纵子完全不表达时，对生长速率的控制通过最大值（C = 0.1）并消失，这反映了该底物存在ATP合成的替代途径。与野生型相比，在H+-ATP酶水平升高时，酶对生长速率的控制变为阴性。缺乏atp操纵子对生长速率的控制的进化背景进行了讨论。
The H+-ATPase plays a central role in Escherichia coli free-energy transduction and hence in E. coli physiology. We here investigate the extent to which this enzyme also controls the growth rate, growth yield, and respiratory rate of E. coli. We modulate the expression of the atp operon and determine the effect on said properties. When quantified in terms of control coefficients, we find that, in the wild-type cell growing on glucose in minimal medium, this key enzyme (H+-ATPase) exerts virtually no control on growth rate (Absolute value of C < 0.01), a minor positive control on growth yield (C = 0.15), and a small but negative control on respiration rate (C = -0.25). The control the enzyme exerts on the consumption rate of the carbon and free-energy substrate is negative (C = -0.15). We also studied how the control coefficients themselves vary with the expression of the atp operon. As the level of expression of the atp operon was reduced, the control exerted by the H+-ATPase on growth rate and growth yield increased slightly; the control on growth rate passed through a maximum (C = 0.1) and disappeared when the atp operon was not expressed at all, reflecting that with this substrate there are alternative routes for ATP synthesis. At elevated levels of the H+-ATPase compared to the wild type, the control exerted by the enzyme on growth rate became negative. The evolutionary context of the absence of control by the atp operon on growth rate is discussed.