The respiratory chain of Corynebacterium glutamicum
The respiratory chain of Corynebacterium glutamicum
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谷氨酸棒杆菌的呼吸链
DOI：
10.1016/s0168-1656(03)00144-5
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发表时间：
2003-09-04
影响因子：
4.1
通讯作者：
Niebisch, A
中科院分区：
文献类型：
--
作者：
Bott, M;Niebisch, A
谷氨酸棒杆菌是一种需氧细菌，需要氧气作为外源电子受体进行呼吸。最近的分子和生物化学分析以及从基因组序列中获得的信息表明，谷氨酸棒杆菌具有一个分支的电子传递链的氧与一些显着的功能。通过氧化各种底物获得的还原当量通过至少八种不同的脱氢酶，即NADH脱氢酶、琥珀酸脱氢酶、苹果酸：醌氧化还原酶、丙酮酸：醌氧化还原酶、D-乳酸脱氢酶、L-乳酸脱氢酶、甘油-3-磷酸脱氢酶和L-脯氨酸脱氢酶转移至甲萘醌。所有这些酶都含有黄素辅因子，除了琥珀酸脱氢酶，都是位于细胞内的单亚基外周膜蛋白。从甲基喹啉开始，电子要么通过细胞色素be，复合物传递到具有低氧亲和力的aa（3）型细胞色素e氧化酶，要么传递到具有高氧亲和力的细胞色素bd型甲基喹啉氧化酶。前一个分支是例外的，因为它不涉及一个单独的细胞色素c进行电子从细胞色素c（1）转移到细胞色素aa（3）的亚基II中的Cu-A中心。相反，细胞色素cl含有两个共价结合的血红素基团，其中一个可能接管单独的细胞色素c的功能。在C.谷氨酸。确定的突变体的表型显示，bc（1）-aa（3）分支，而不是bd分支，是主要的有氧生长在基本培养基中的重要性。氧化磷酸化效率的变化所造成的呼吸链的质的变化，或由一个有缺陷的F1 F0-ATP合酶被发现有强烈的影响代谢和氨基酸的生产。因此，氧化磷酸化系统是通过代谢工程提高谷氨酸棒杆菌氨基酸生产率的一个有吸引力的目标。(C)2003 Elsevier B. V.保留所有权利。
Corynebacterium glutamicum is an aerobic bacterium that requires oxygen as exogenous electron acceptor for respiration. Recent molecular and biochemical analyses together with information obtained from the genome sequence showed that C glutamicum possesses a branched electron transport chain to oxygen with some remarkable features. Reducing equivalents obtained by the oxidation of various substrates are transferred to menaquinone via at least eight different dehydrogenases, i.e. NADH dehydrogenase, succinate dehydrogenase, malate:quinone oxidoreductase, pyruvate:quinone oxidoreductase, D-lactate dehydrogenase, L-lactate dehydrogenase, glycerol-3-phosphate dehydrogenase and L-proline dehydrogenase. All these enzymes contain a flavin cofactor and, except succinate dehydrogenase, are single subunit peripheral membrane proteins located inside the cell. From menaquinol, the electrons are passed either via the cytochrome be, complex to the aa(3)-type cytochrome e oxidase with low oxygen affinity, or to the cytochrome bd-type menaquinol oxidase with high oxygen affinity. The former branch is exceptional, in that it does not involve a separate cytochrome c for electron transfer from cytochrome c(1) to the Cu-A center in subunit II of cytochrome aa(3). Rather, cytochrome cl contains two covalently bound heme groups, one of which presumably takes over the function of a separate cytochrome c. The be, complex and cytochrome aa3 oxidase form a supercomplex in C. glutamicum. The phenotype of defined mutants revealed that the bc(1)-aa(3) branch, but not the bd branch, is of major importance for aerobic growth in minimal medium. Changes of the efficiency of oxidative phosphorylation caused by qualitative changes of the respiratory chain or by a defective F1F0-ATP synthase were found to have strong effects on metabolism and amino acid production. Therefore, the system of oxidative phosphorylation represents an attractive target for improving amino acid productivity of C glutamicum by metabolic engineering. (C) 2003 Elsevier B.V. All rights reserved.