Unique glycine-activated riboswitch linked to glycine-serine auxotrophy in SAR11.
Unique glycine-activated riboswitch linked to glycine-serine auxotrophy in SAR11.
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DOI：
10.1111/j.1462-2920.2008.01758.x
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发表时间：
2009-01
影响因子：
5.1
通讯作者：
Giovannoni, Stephen J.
中科院分区：
文献类型：
--
作者：
Tripp, H. James;Schwalbach, Michael S.;Meyer, Michelle M.;Kitner, Joshua B.;Breaker, Ronald R.;Giovannoni, Stephen J.
海洋细菌“泛Pelagibacter Candidatus Pelagibacter ubique”的基因组序列和随后的分析表明，虽然它的基因组和许多专性寄生虫一样小，但它仍然拥有代谢库，使其能够成长为海洋中最成功的自由活细胞之一。基于代谢重建的早期报告表明SAR11细胞对所有氨基酸都是原生营养细胞。然而，在这里，我们报告的实验证据表明，“土地。P. ubique '对甘氨酸和丝氨酸具有有效的营养缺陷。在向海水中添加葡萄糖和醋酸盐以提供有机碳的情况下，在含有过量其他营养物质的培养基中添加125 nM至1.5 μM的甘氨酸，最大细胞密度从1.14 ×106 cells ml - 1线性增加到8.16 ×106 cells ml - 1 （R2 = 0.992）。丝氨酸能在1.5 μM处取代甘氨酸。萤石。P. ubique '在苹果酸合成酶之前含有甘氨酸激活的核糖开关，这是SAR11组中保守的不寻常的基因组背景。苹果酸合成酶在中枢代谢中发挥关键作用，使TCA中间体通过乙醛酸循环再生。对这种核糖开关的体外分析表明，它只对甘氨酸有反应，而对结构类似的甘氨酸、甜菜碱、苹果酸盐、乙醛酸盐、乙醇酸盐、丙氨酸、丝氨酸或苏氨酸没有反应。我们的结论是。因此，P. ubique '是一种甘氨酸-丝氨酸营养不良生物，似乎使用细胞内甘氨酸水平来调节其对碳的生物合成和能量的使用。比较基因组学和宏基因组学表明，这些结论可能适用于大部分SAR11进化支。
The genome sequence of the marine bacterium ‘Candidatus Pelagibacter ubique’ and subsequent analyses have shown that, while it has a genome as small as many obligate parasites, it nonetheless possesses a metabolic repertoire that allows it to grow as one of the most successful free-living cells in the ocean. An early report based on metabolic reconstruction indicated that SAR11 cells are prototrophs for all amino acids. However, here we report experimental evidence that ‘Cand. P. ubique’ is effectively auxotrophic for glycine and serine. With glucose and acetate added to seawater to supply organic carbon, the addition of 125 nM to 1.5 μM glycine to growth medium containing all other nutrients in excess resulted in a linear increase in maximum cell density from 1.14 ×106 cells ml−1 to 8.16 ×106 cells ml−1 (R2 = 0.992). Serine was capable of substituting for glycine at 1.5 μM. ‘Cand. P. ubique’ contains a glycine-activated riboswitch preceding malate synthase, an unusual genomic context that is conserved in the SAR11 group. Malate synthase plays a critical role in central metabolism by enabling TCA intermediates to be regenerated through the glyoxylate cycle. In vitro analysis of this riboswitch indicated that it responds solely to glycine but not close structural analogs such as glycine betaine, malate, glyoxylate, glycolate, alanine, serine, or threonine. We conclude that ‘Cand. P. ubique’ is therefore a glycine-serine auxotroph that appears to use intracellular glycine level to regulate its use of carbon for biosynthesis and energy. Comparative genomics and metagenomics indicate that these conclusions may hold throughout much of the SAR11 clade.
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DOI：
10.1016/s0967-0637(97)00090-3
发表时间：
1997-12-01
影响因子：
2.4
作者：
Leboulanger, C;Oriol, L;Descolas-Gros, C
通讯作者：
Descolas-Gros, C
影响因子：
4.5
作者：
MOPPER, K;LINDROTH, P
通讯作者：
LINDROTH, P
影响因子：
4.8
作者：
Pellicer, MT;Fernandez, C;Baldomà, L
通讯作者：
Baldomà, L
影响因子：
2.9
作者：
Leboulanger, C;Martin-Jezequel, V;Jupin, HJ
通讯作者：
Jupin, HJ
影响因子：
3.2
作者：
RAVNIKAR, PD;SOMERVILLE, RL
通讯作者：
SOMERVILLE, RL