Adaptations to a Loss-of-Function Mutation in the Betaproteobacterium Aromatoleum aromaticum: Recruitment of Alternative Enzymes for Anaerobic Phenylalanine Degradation
Adaptations to a Loss-of-Function Mutation in the Betaproteobacterium Aromatoleum aromaticum: Recruitment of Alternative Enzymes for Anaerobic Phenylalanine Degradation
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芳香β变形菌中功能丧失突变的适应：用于厌氧苯丙氨酸降解的替代酶的招募
DOI：
10.1128/jb.00383-17
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发表时间：
2017
影响因子：
3.2
通讯作者：
J. Heider
中科院分区：
文献类型：
--
作者：
G. Schmitt;F. Arndt;J. Kahnt;J. Heider
苯丙氨酸在β-变形杆菌芳香族中的厌氧降解包括转氨作用和脱羧作用，生成苯乙醛，然后氧化生成苯乙酸。后一种反应同时由两种酶催化，一种高度特异性的苯乙醛脱氢酶（PDH）和一种非特异性的钨依赖性醛氧化还原酶（AOR）。为了增加AOR的合成，我们构建了一个缺少PDH基因的突变体。该突变体仍然生长在苯丙氨酸上，在含有钨酸盐的培养基上表现出增加的AOR活性。在没有钨酸盐的情况下，突变体最初表现出严重的生长缺陷，但在较长的孵育时间后恢复生长。此外，突变体的生长速率增加，在几个再接种周期的钨酸盐精通或缺乏媒体，达到相同的值记录在野生型菌株。我们确认AOR作为钨酸盐供应条件下的主要替代酶服务苯丙氨酸降解，并确定和表征了替代NAD依赖性醛脱氢酶AldB在钨酸盐缺乏条件下接管功能。从适应的文化在任一生长条件下的各自的基因的序列分析显示，在上游区域的thepietamine操纵子和突变的编码区域内的aldB，这是可能参与观察到的适应的缺失突变体恢复快速增长的Phe.IMPORTANCEThe β-proteobacterium Aromateliaromaticum降解许多芳香族化合物在purifying条件下。苯丙氨酸降解的一个步骤是由两个同时诱导的酶催化的，这两个酶是NAD（P）依赖性苯乙醛脱氢酶和含W醛氧化还原酶。我们在这里报告，后者完全补充了构建缺失突变体缺乏苯乙醛脱氢酶的基因，并在几次再接种后过量生产。此外，另一种NAD依赖性脱氢酶被募集以在不含钨酸盐的培养基中恢复生长，这不允许产生醛氧化还原酶。这种替代酶是过度生产，似乎已经获得了活性中心的点突变。我们的研究说明了环境重要性细菌在短短几代内适应其代谢途径以应对新挑战的灵活性。
Anaerobic phenylalanine (Phe) degradation in the betaproteobacterium Aromatoleum aromaticum involves transamination and decarboxylation to phenylacetaldehyde, followed by oxidation to phenylacetate. The latter reaction is catalyzed simultaneously by two enzymes, a highly specific phenylacetaldehyde dehydrogenase (PDH) and a rather unspecific tungsten-dependent aldehyde oxidoreductase (AOR). Attempting to establish increased synthesis of AOR, we constructed a mutant lacking the gene for PDH. This mutant still grew on phenylalanine, exhibiting increased AOR activities on medium containing tungstate. In the absence of tungstate, the mutant showed initially severe growth deficiency, but it resumed growth on Phe after longer incubation times. Moreover, the growth rates of the mutant increased during several reinoculation cycles on either tungstate-proficient or -deficient media, reaching the same values as recorded in wild-type strains. We confirmed AOR as the major alternative enzyme serving Phe degradation under tungstate-supplied conditions and identified and characterized the alternative NAD-dependent aldehyde dehydrogenase AldB taking over the function under tungstate-deficient conditions. Sequence analysis of the respective genes from adapted cultures under either growth condition revealed a mutation in the upstream region of theaoroperon and a mutation within the coding region ofaldB, which are likely involved in the observed adaptation of the deletion mutant to regain fast growth on Phe.IMPORTANCEThe betaproteobacterium Aromatoleum aromaticum degrades many aromatic compounds under denitrifying conditions. One of the steps of phenylalanine degradation is catalyzed by two simultaneously induced enzymes, a NAD(P)-dependent phenylacetaldehyde dehydrogenase and a W-containing aldehyde oxidoreductase. We report here that the latter fully complements a constructed deletion mutant lacking the gene for phenylacetaldehyde dehydrogenase and is overproduced after several reinoculations. Moreover, an alternative NAD-dependent dehydrogenase is recruited to resume growth in tungstate-free medium, which does not allow the production of aldehyde oxidoreductase. This alternative enzyme is overproduced and seems to have acquired a point mutation in the active center. Our research illustrates the flexibility of environmentally important bacteria in adapting their metabolic pathways to new challenges within only a few generations.
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来自超嗜热古菌北海热球菌的新型含钨甲醛铁氧还蛋白氧化还原酶的表征。
影响因子：
4.8
作者：
S. Mukund;M. Adams
通讯作者：
M. Adams
DOI：
10.1128/mr.55.3.371-394.1991
发表时间：
1991-09
期刊：
Microbiological Reviews
影响因子：
--
作者：
J. Collado-Vides;B. Magasanik;J. D. Gralla
通讯作者：
J. Collado-Vides;B. Magasanik;J. D. Gralla
格罗宁根大学鉴定参与 1, 2-二氯乙烷降解的氯乙醛脱氢酶
DOI：
--
发表时间：
2017
期刊：
影响因子：
--
作者：
Jan Van Der Ploeg;M. Smidt;Andrew S. Landa;Dick B. Janssen
通讯作者：
Dick B. Janssen
影响因子：
3.5
作者：
INOUE, H;NOJIMA, H;OKAYAMA, H
通讯作者：
OKAYAMA, H
影响因子：
3.2
作者：
Debnar-Daumler, Carlotta;Seubert, Andreas;Heider, Johann
通讯作者：
Heider, Johann