GENETIC ORGANIZATION OF THE MAU GENE-CLUSTER IN METHYLOBACTERIUM-EXTORQUENS AM1 - COMPLETE NUCLEOTIDE-SEQUENCE AND GENERATION AND CHARACTERISTICS OF MAU MUTANTS
GENETIC ORGANIZATION OF THE MAU GENE-CLUSTER IN METHYLOBACTERIUM-EXTORQUENS AM1 - COMPLETE NUCLEOTIDE-SEQUENCE AND GENERATION AND CHARACTERISTICS OF MAU MUTANTS
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DOI：
10.1128/jb.176.13.4052-4065.1994
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发表时间：
1994-07-01
影响因子：
3.2
通讯作者：
LIDSTROM, ME
中科院分区：
文献类型：
--
作者：
CHISTOSERDOV, AY;CHISTOSERDOVA, LV;LIDSTROM, ME
确定了扭扭甲基杆菌 AM1 的甲胺利用 (mau) 基因区域的核苷酸序列。发现了 11 个基因（mauFBEDACJGLMN）的开放阅读框，全部以相同方向转录。 mauB、mauA 和 manC 基因分别编码周质甲胺脱氢酶 (MADH) 大亚基和小亚基多肽以及阿霉素。 mauD、mauG、mauL 和 mauM 的产物也被预测为周质。 mauF、mauE 和 mauN 的产物预计与膜相关。 mnuJ 产物是 mau 基因簇编码的唯一多肽，预计其存在于细胞质中。计算机分析表明，MauG 多肽含有两个假定的血红素结合位点，MauM 和 MauN 多肽分别具有四个和两个 FeS 簇特征。通过mauF、mauB、mauE、mauD、mau4、mauG和mauL中的插入产生的突变体不能以甲胺或任何其他伯胺作为碳源生长，而通过mauC中的插入产生的突变体不能利用甲胺作为碳源，而是利用C1至C16正烷基胺作为碳源。 mauJ、mauM 和 mauN 中的插入突变不会损害突变体利用伯正烷基胺作为碳源的能力。所有 mau 突变体都能够利用甲胺作为氮源，这意味着存在替代的（甲基）胺氧化系统，并且检测到 N-甲基谷氨酸脱氢酶活性较低。发现mauD、mauE和mauF突变体缺乏MADH小亚基多肽并且MADH大亚基多肽的量减少。在mauG和maul突变体中，MADH大亚基和小亚基多肽以野生型水平存在，尽管这些菌株中的MADH没有功能。此外，MauG 与假单胞菌属的细胞色素 c 过氧化物酶具有序列相似性。来自脱氮副球菌的 mauA、mauD 和 mauE 基因以及来自甲基嗜甲基菌 W3A1 的 mauD 和 mauG 基因能够补充扭力分枝杆菌 AM1 的相应突变体，证实了它们的功能等价性。对来自M.extorqaens AM1、P.denitificans和Thiobacillus versutus的配对基因编码的多肽的氨基酸序列进行比较表明，它们具有相当大的相似性。
The nucleotide sequence of the methylamine utilization (mau) gene region from Methylobacterium extorquens AM1 was determined. Open reading frames for 11 genes (mauFBEDACJGLMN) were found, all transcribed in the same orientation. The mauB, mauA, and manC genes encode the periplasmic methylamine dehydrogenase (MADH) large and small subunit polypeptides and amicyanin, respectively. The products of mauD, mauG, mauL, and mauM were also predicted to be periplasmic. The products of mauF, mauE, and mauN were predicted to be membrane associated. The mnuJ product is the only polypeptide encoded by the mau gene cluster which is predicted to be cytoplasmic. Computer analysis showed that the MauG polypeptide contains two putative heme binding sites and that the MauM and MauN polypeptides have four and two FeS cluster signatures, respectively. Mutants generated by insertions in mauF, mauB, mauE, mauD, mau4, mauG, and mauL were not able to grow on methylamine or any other primary amine as carbon sources, while a mutant generated from an insertion in mauC was not able to utilize methylamine as a source of carbon but utilized C, to C, n-alkylamines as carbon sources. Insertion mutations in mauJ, mauM, and mauN did not impair the ability of the mutants to utilize primary n-alkylamines as carbon sources. All mau mutants were able to utilize methylamine as a nitrogen source, implying the existence of an alternative (methyl)amine oxidation system, and a low activity of N-methylglutamate dehydrogenase was detected. The mauD, mauE, and mauF mutants were found to lack the MADH small subunit polypeptide and have a decreased amount of the MADH large subunit polypeptide. In the mauG and maul mutants, the MADH large and small subunit polypeptides were present at wild-type levels, although the MADHs in these strains were not functional. In addition, MauG has sequence similarity to cytochrome c peroxidase from Pseudomonas sp. The mauA, mauD, and mauE genes from Paracoccus denitrificans and the mauD and mauG genes from Methylophilus methylotrophus W3A1 were able to complement corresponding mutants of M. extorquens AM1, confirming their functional equivalence. Comparison of amino acid sequences of polypeptides encoded by mate genes from M. extorqaens AM1, P. denitrificans, and Thiobacillus versutus shows that they have considerable similarity.