The 17-gene ethanolamine (eut) operon of Salmonella typhimurium encodes five homologues of carboxysome shell proteins
The 17-gene ethanolamine (eut) operon of Salmonella typhimurium encodes five homologues of carboxysome shell proteins
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DOI：
10.1128/jb.181.17.5317-5329.1999
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发表时间：
1999-09-01
影响因子：
3.2
通讯作者：
Roth, J
中科院分区：
文献类型：
--
作者：
Kofoid, E;Rappleye, C;Roth, J
鼠伤寒沙门氏菌的eut操纵子编码参与乙醇胺钴胺素依赖性降解的蛋白质。先前的遗传分析揭示了需氧使用乙醇胺所需的六个eat基因;一个（eutR）编码正调节子，其介导维生素B-12加乙醇胺对操纵子的诱导。eut操纵子的DNA序列包括17个基因，表明一个比遗传学揭示的更复杂的途径。我们已经将序列中的开放阅读框与先前鉴定的每个基因相关联。用Tn 10衍生的转座因子T-POP进行的非极性插入和缺失突变表明，在测试的条件下，11个先前未检测到的eat基因中至少有10个没有Eut表型。在这些基因中，有5个编码的蛋白质与其他生物体中作为碳氧体外壳蛋白的蛋白质有明显的同源性，这种细菌细胞器存在于光合细菌和硫氧化细菌中，可能通过浓缩CO2和排除氧气来固定CO2。沙门氏菌的eut操纵子中存在这些同源物表明CO2固定可能是沙门氏菌中乙醇胺催化剂的一个特征。
The eut operon of Salmonella typhimurium encodes proteins involved in the cobalamin-dependent degradation of ethanolamine. Previous genetic analysis revealed six eat genes that are needed for aerobic use of ethanolamine; one (eutR), encodes a positive regulator which mediates induction of the operon by vitamin B-12 plus ethanolamine. The DNA sequence of the eut operon included 17 genes, suggesting a more complex pathway than that revealed genetically. We have correlated an open reading frame in the sequence with each of the previously identified genes. Nonpolar insertion and deletion mutations made with the Tn10-derived transposable element T-POP showed that at least 10 of the 11 previously undetected eat genes have no Eut phenotype under the conditions tested. Of the dispensable eut genes, five encode apparent homologues of proteins that serve (in other organisms) as shell proteins of the carboxysome, This bacterial organelle, found in photosynthetic and sulfur-oxidizing bacteria, may contribute to CO2 fixation by concentrating CO2 and excluding oxygen. The presence of these homologues in the eut operon of Salmonella suggests that CO2 fixation may be a feature of ethanolamine catabolism in Salmonella.