Pathways and Substrate Specificity of DMSP Catabolism in Marine Bacteria of the Roseobacter Clade
Pathways and Substrate Specificity of DMSP Catabolism in Marine Bacteria of the Roseobacter Clade
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DOI：
10.1002/cbic.200900668
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发表时间：
2010-02-15
期刊：
影响因子：
3.2
通讯作者：
Brock, Nelson L.
中科院分区：
文献类型：
--
作者：
Dickschat, Jeroen S.;Zell, Claudia;Brock, Nelson L.
采用气相色谱-质谱联用技术研究了褐盖棕、吲哚海蛞蝓和甲藻释放的挥发物，并鉴定了几种甲基巯基衍生的硫挥发物。海洋中一个重要的硫源是藻类代谢物二甲基磺基丙酸盐（DMSP）。将标记的[（2）H（6）]DMSP进料至细菌以研究该化合物通过裂解途径至[（2）H（6）]二甲硫醚或脱甲基途径至[（2）H（3）]-3-（甲硫基）丙酸和裂解至[（2）H（3）]MeSH的挥发物的产生。[（2）H（6）]DMSP被所有三种物种有效地转化为[（2）H（3）]MeSH。合成了几种DMSP衍生物并用于饲养实验。甲基化乙基甲基磺基丙酸酯和二甲基硒基丙酸酯观察到强脱烷基化活性，如由EtSH-和MeSeH-衍生的挥发物的形成所指示的，而没有挥发物由二甲基碲基丙酸酯形成。相反，二乙基磺基丙酸酯的脱烷基化活性强烈降低，导致在P. gallaeciensis和O. indolifex，D. Shiesin产生相关的氧化产物二乙基砜。二乙硫醚和二乙砜的形成需要裂解途径，这对[（2）H（6）]DMSR没有活性。这些观察结果可以通过两种竞争途径之间的转移分布来解释，这是由于乙基化底物的脱烷基化受阻。
The volatiles released by Phaeobacter gallaeciensis, Oceonibulbus indolifex and Dinoroseobacter shibae have been investigated by GC-MS, and several MeSH-derived sulfur volatiles have been identified. An important sulfur source in the oceans is the algal metabolite dimethylsulfoniopropionate (DMSP). Labelled [(2)H(6)]DMSP was fed to the bacteria to investigate the production of volatiles from this compound through the lysis pathway to [(2)H(6)]dimethylsulfide or the demethylation pathway to [(2)H(3)]-3-(methylmercapto)prop ionic acid and lysis to [(2)H(3)]MeSH. [(2)H(6)]DMSP was efficiently converted to [(2)H(3)]MeSH by all three species. Several DMSP derivatives were synthesised and used in feeding experiments. Strong dealkylation activity was observed for the methylated ethyl methyl sulfoniopropionate and dimethylseleniopropionate, as indicated by the formation of EtSH- and MeSeH-derived volatiles, whereas no volatiles were formed from dimethyltelluriopropionate. In contrast, the dealkylation activity for diethylsulfoniopropionate was strongly reduced, resulting in only small amounts of EtSH-derived volatiles accompanied by diethyl sulfide in P. gallaeciensis and O. indolifex, while D. shibae produced the related oxidation product diethyl sulfone. The formation of diethyl sulfide and diethyl sulfone requires the lysis pathway, which is not active for [(2)H(6)]DMSR These observations can be explained by a shifted distribution between the two competing pathways due to a blocked dealkylation of ethylated substrates.