THE MOXFG REGION ENCODES 4 POLYPEPTIDES IN THE METHANOL-OXIDIZING BACTERIUM METHYLOBACTERIUM SP STRAIN AM1
THE MOXFG REGION ENCODES 4 POLYPEPTIDES IN THE METHANOL-OXIDIZING BACTERIUM METHYLOBACTERIUM SP STRAIN AM1
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DOI：
10.1128/jb.170.5.2254-2262.1988
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发表时间：
1988-05-01
影响因子：
3.2
通讯作者：
LIDSTROM, ME
中科院分区：
文献类型：
--
作者：
ANDERSON, DJ;LIDSTROM, ME
由甲醇氧化(MOX)操纵子编码的多肽。利用体内T7 RNA聚合酶/启动子耦合基因表达系统，在大肠杆菌中表达了AM1菌株。此前已有两个mox基因定位于该区域：moxF，编码甲醇脱氢酶(Medh)多肽的基因；moxG，据信编码可溶性c型细胞色素c1的基因。在本研究中，发现了4个由moxFG区编码的多肽，分别命名为moxF、-J、-G和-I。基因(5‘~3’)的排列方式为moxFJGI。通过蛋白质免疫印迹分析确定了四种多肽中的三种。MoxF的产物是MR-60,000多肽，被证实是MedH多肽。MoxG的产物MR-20,000被鉴定为成熟的细胞色素CL，而Moxi的产物MR-12,000被鉴定为与全酶结合的MEH相关多肽。无法确定MR-30,000多肽(moxJ基因产物)的身份。MR-12,000-Medh相关多肽的功能尚不清楚。然而，在缺乏MR-60,000 MedH亚基的突变体中不存在它，并且似乎Medh相关多肽的稳定性取决于MR-60,000 Medh多肽的存在。我们的数据表明，MR-30,000和-12,000两个多肽都参与了甲醇氧化，这将使甲烷杆菌中mox基因的数量增加到12个。菌株AM1。
The polypeptides encoded by a putative methanol oxidation (mox) operon of Methylobacterium sp. strain AM1 were expressed in Escherichia coli, using a coupled in vivo T7 RNA polymerase/promoter gene expression system. Two mox genes had been previously mapped to this region: moxF, the gene encoding the methanol dehydrogenase (MeDH) polypeptide; and moxG, a gene believed to encode a soluble type c cytochrome, cytochrome cL. In this study, four polypeptides of Mr 60,000, 30,000, 20,000, and 12,000 were found to be encoded by the moxFG region and were tentatively designated moxF, -J, -G, and -I, respectively. The arrangement of the genes (5'' to 3'') was found to be moxFJGI. The identities of three of the four polypeptides were determined by protein immunoblot analysis. The product of moxF, the Mr-60,000 polypeptide, was confirmed to be the MeDH polypeptide. The product of moxG, the Mr-20,000 polypeptide, was identified as mature cytochrome cL, and the product of moxI, the Mr-12,000 polypeptide, was identified as a MeDH-associated polypeptide that copurifies with the holoenzyme. The identity of the Mr-30,000 polypeptide (the moxJ gene product) could not be determined. The function of the Mr-12,000 MeDH-associated polypeptide is not yet clear. However, it is not present in mutants that lack the Mr-60,000 MeDH subunit, and it appears that the stability of the MeDH-associated polypeptide is dependent on the presence of the Mr-60,000 MeDH polypeptide. Our data suggest that both the Mr-30,000 and -12,000 polypeptides are involved in methanol oxidation, which would bring to 12 the number of mox genes in Methylobacterium sp. strain AM1.