DSYB catalyses the key step of dimethylsulfoniopropionate biosynthesis in many phytoplankton
DSYB catalyses the key step of dimethylsulfoniopropionate biosynthesis in many phytoplankton
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DOI：
10.1038/s41564-018-0119-5
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发表时间：
2018-04-01
影响因子：
28.3
通讯作者：
Todd, Jonathan D.
中科院分区：
文献类型：
--
作者：
Curson, Andrew R. J.;Williams, Beth T.;Todd, Jonathan D.
二甲基硫基丙酸酯（DMSP）是一种重要的有机硫分子，也是合成二甲基硫醚的主要前体。这些化合物是重要的信息化学物质，是海洋微生物的关键营养物质，并参与全球硫循环，大气化学和云的形成（1-3）。DMSP的产生被认为仅限于真核生物，但异养细菌也可以通过大多数浮游植物使用的途径产生DMSP（4），最近发现了催化细菌中该途径关键步骤的DsyB酶（5）。然而，真核浮游植物可能产生地球上大部分的DMSP，但没有DMSP生物合成基因已被确定在任何这样的生物。在这里，我们确定功能dsyB同系物，称为DSYB，在许多浮游植物和珊瑚。DSYB是一种甲基硫代羟基丁酸甲基转移酶，定位于叶绿体和线粒体的附着植物Prymnesium parvum，和稳定的同位素跟踪实验支持这些细胞器的DMSP合成的网站。DSYB的转录水平随着DMSP浓度的增加，在不同的浮游植物和细胞内DMSP的指示。真核生物DSYB序列的鉴定，沿着细菌DSYB，提供了第一个分子工具来预测真核生物和原核生物对全球DMSP生产的相对贡献。此外，进化分析表明，真核生物DSYB起源于细菌，并在其进化的早期传递给真核生物。
Dimethylsulfoniopropionate (DMSP) is a globally important organosulfur molecule and the major precursor for dimethyl sulfide. These compounds are important info-chemicals, key nutrients for marine microorganisms, and are involved in global sulfur cycling, atmospheric chemistry and cloud formation(1-3). DMSP production was thought to be confined to eukaryotes, but heterotrophic bacteria can also produce DMSP through the pathway used by most phytoplankton(4), and the DsyB enzyme catalysing the key step of this pathway in bacteria was recently identified(5). However, eukaryotic phytoplankton probably produce most of Earth's DMSP, yet no DMSP biosynthesis genes have been identified in any such organisms. Here we identify functional dsyB homologues, termed DSYB, in many phytoplankton and corals. DSYB is a methylthiohydroxybutryate methyltransferase enzyme localized in the chloroplasts and mitochondria of the haptophyte Prymnesium parvum, and stable isotope tracking experiments support these organelles as sites of DMSP synthesis. DSYB transcription levels increased with DMSP concentrations in different phytoplankton and were indicative of intracellular DMSP. Identification of the eukaryotic DSYB sequences, along with bacterial dsyB, provides the first molecular tools to predict the relative contributions of eukaryotes and prokaryotes to global DMSP production. Furthermore, evolutionary analysis suggests that eukaryotic DSYB originated in bacteria and was passed to eukaryotes early in their evolution.