Comparative genomics and mutagenesis analyses of choline metabolism in the marine Roseobacter clade.
Comparative genomics and mutagenesis analyses of choline metabolism in the marine Roseobacter clade.
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DOI：
10.1111/1462-2920.12943
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发表时间：
2015-12
影响因子：
5.1
通讯作者：
Chen Y
中科院分区：
文献类型：
--
作者：
Lidbury I;Kimberley G;Scanlan DJ;Murrell JC;Chen Y
胆碱在海洋真核生物中普遍存在，并且似乎广泛分布于海洋表面沃茨中;然而，对海洋细菌代谢胆碱的了解甚少。在这里，使用比较基因组学和分子遗传学的方法，我们揭示了胆碱catalysts的能力是广泛的海洋异养的海洋蔷薇属分支（MRC）。利用模式菌Rugeria pomeroyi，我们证实了分别编码胆碱脱氢酶、甜菜碱醛脱氢酶和胆碱硫酸酯酶的bet A、bet B和bet C基因参与胆碱代谢。bet T基因编码一种有机溶质转运蛋白，对胆碱的快速摄取是必需的，但对甘氨酸甜菜碱（GBT）不是必需的。胆碱和GBT作为唯一碳源的生长导致这些富氮化合物再矿化为铵。胆碱中甲基的氧化需要由波氏红酵母中fhs编码的甲酰四氢叶酸合成酶，其缺失导致GBT的不完全降解。我们证明，这是由于胆碱催化剂所需的还原当量的供应不平衡，这可以通过添加甲酸盐来缓解。总之，我们的研究结果表明，胆碱代谢是无处不在的MRC和揭示的作用Fhs在甲基氧化的R . pomeroyi。
Choline is ubiquitous in marine eukaryotes and appears to be widely distributed in surface marine waters; however, its metabolism by marine bacteria is poorly understood. Here, using comparative genomics and molecular genetic approaches, we reveal that the capacity for choline catabolism is widespread in marine heterotrophs of the marine Roseobacter clade (MRC). Using the model bacterium R uegeria pomeroyi, we confirm that the bet A, bet B and bet C genes, encoding choline dehydrogenase, betaine aldehyde dehydrogenase and choline sulfatase, respectively, are involved in choline metabolism. The bet T gene, encoding an organic solute transporter, was essential for the rapid uptake of choline but not glycine betaine (GBT). Growth of choline and GBT as a sole carbon source resulted in the re‐mineralization of these nitrogen‐rich compounds into ammonium. Oxidation of the methyl groups from choline requires formyltetrahydrofolate synthetase encoded by fhs in R . pomeroyi, deletion of which resulted in incomplete degradation of GBT. We demonstrate that this was due to an imbalance in the supply of reducing equivalents required for choline catabolism, which can be alleviated by the addition of formate. Together, our results demonstrate that choline metabolism is ubiquitous in the MRC and reveal the role of Fhs in methyl group oxidation in R . pomeroyi.