EXPERIMENTAL EVOLUTION OF A METABOLIC PATHWAY FOR ETHYLENE-GLYCOL UTILIZATION BY ESCHERICHIA-COLI
EXPERIMENTAL EVOLUTION OF A METABOLIC PATHWAY FOR ETHYLENE-GLYCOL UTILIZATION BY ESCHERICHIA-COLI
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DOI：
10.1128/jb.153.1.134-139.1983
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发表时间：
1983-01-01
影响因子：
3.2
通讯作者：
AGUILAR, J
中科院分区：
文献类型：
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作者：
BORONAT, A;CABALLERO, E;AGUILAR, J
从能够以丙二醇为唯一碳源和能源生长的突变体中获得了能够以乙二醇为唯一碳源和能源生长的大肠杆菌自发突变体。从野生型大肠杆菌中获取利用乙二醇的突变体的尝试未成功。利用乙二醇的突变体的两个主要特征是：丙二醇氧化还原酶活性增加，该酶存在于亲本菌株（一种丙二醇阳性菌株）中，它也能将乙二醇转化为乙醇醛；以及乙醇醛脱氢酶高活性的组成型合成，该酶将乙醇醛转化为乙醇酸。乙醇酸通过乙醇酸途径代谢，该途径存在于野生型细胞中；这通过在以乙二醇为生长底物的细胞中诱导出该途径中的第一种酶——乙醇酸氧化酶得以表明。乙醇醛脱氢酶被部分鉴定为大肠杆菌中这种新代谢途径的一种酶，并且乙醇酸被确定为该反应的产物。这种酶使用NAD和NADP作为辅酶，尽管NADP依赖的活性比NAD依赖的活性低约10倍。[14C]乙二醇的摄取依赖于能够代谢乙二醇的酶的存在。乙醇醛和乙醇酸被确定为该途径中的中间代谢产物。
Spontaneous mutants of E. coli able to grow on ethylene glycol as a sole source of C and energy were obtained from mutants that could grow on propylene glycol. Attempts to obtain ethylene glycol-utilizing mutants from wild-type E. coli were unsuccessful. The 2 major characteristics of the ethylene glycol-utilizing mutants were increased activities of propanediol oxidoreductase, an enzyme present in the parental strain (a propylene glycol-positive strain), which also converted ethylene glycol into glycolaldehyde; and constitutive synthesis of high activities of glycolaldehyde dehydrogenase, which converted glycolaldehyde to glycolate. Glycolate was metabolized via the glycolate pathway, which was present in the wild-type cells; this was indicated by the induction in ethylene glycol-grown cells of glycolate oxidase, the first enzyme in the pathway. Glycolaldehyde dehydrogenase was partially characterized as an enzyme of this new metabolic pathway in E. coli and glycolate was identified as the product of the reaction. This enzyme used NAD and NADP as coenzymes, although the NADP-dependent activity was about 10 times lower than the NAD-dependent activity. Uptake of [14C]ethylene glycol was dependent on the presence of the enzymes capable of metabolism of ethylene glycol. Glycolaldehyde and glycolate were identified as intermediate metabolites in the pathway.