Function of the cytochrome bc1-aa3 branch of the respiratory network in mycobacteria and network adaptation occurring in response to its disruption
Function of the cytochrome bc1-aa3 branch of the respiratory network in mycobacteria and network adaptation occurring in response to its disruption
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DOI：
10.1128/jb.187.18.6300-6308.2005
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发表时间：
2005-09-01
影响因子：
3.2
通讯作者：
Mizrahi, V
中科院分区：
文献类型：
--
作者：
Matsoso, LG;Kana, BD;Mizrahi, V
耻垢分枝杆菌的需氧电子传递链可以终止于三种可能的末端氧化酶复合物之一。从甲基萘醌-甲基萘醌库到细胞色素be复合物，最后到aa（3）型细胞色素c氧化酶的电子传递途径的结构和功能进行了表征。M：发现在BE、复合物和细胞色素C氧化酶亚基II中具有突变的耻垢病菌株严重生长受损，证实了该呼吸途径对需氧条件下分枝杆菌生长的重要性。该途径的破坏导致呼吸网络的适应，其特征在于cydAB的显著上调，cydAB编码生物能量效率较低且微需氧诱导的细胞色素bd型甲萘醌氧化酶，其是M生长所需的。氧气限制条件下的包皮垢。通过使用M的部分基因组微阵列对bc（1）缺陷突变株的表达谱分析，揭示了该生物体对通过终止于bd型氧化酶的分支的电子通量重新路由的适应的进一步见解。富含必需基因的包皮环腺。尽管表达谱表明呼吸链还原状态的增加，但bc（1）-aa（3）途径的阻断不会诱导M的哨兵基因。由氧饥饿诱导并由DosR双组分调节剂调节的smeglobulin。
The aerobic electron transport chain in Mycobacterium smegmatis can terminate in one of three possible terminal oxidase complexes. The structure and function of the electron transport pathway leading from the menaquinol-menaquinone pool to the cytochrome be, complex and terminating in the aa(3)-type cytochrome c oxidase was characterized. M: smegmatis strains with mutations in the be, complex and in subunit II of cyctochome c oxidase were found to be profoundly growth impaired, confirming the importance of this respiratory pathway for mycobacterial growth under aerobic conditions. Disruption of this pathway resulted in an adaptation of the respiratory network that is characterized by a marked up-regulation of cydAB, which encodes the bioenergetically less efficient and microaerobically induced cytochrome bd-type menaquinol oxidise that is required for the growth of M. smegmatis under O-2-limiting conditions. Further insights into the adaptation of this organism to rerouting of the electron flux through the branch terminating in the bd-type oxidase were revealed by expression profiling of the bc(1)-deficient mutant strain using a partial-genome microarray of M. smegmatis that is enriched in essential genes. Although the expression profile was indicative of an increase in the reduced state of the respiratory chain, blockage of the bc(1)-aa(3) pathway did not induce the sentinel genes of M. smegmatis that are induced by oxygen starvation and are regulated by the DosR two-component regulator.