DMSP的生物合成与裂解及其在硫循环中的作用  

Biosynthesis and cleavage of DMSP and their roles in global sulfur cycle

作　　者：张晓华[1,2] 刘骥 柳敬丽 郑艳芬 Zhang Xiao-Hua;Liu Ji;Liu Jingli;Zheng Yanfen(College of Marine Life Sciences,Ocean University of China;Yushan Road,Qingdao 266003,China;Laboratory for Marine Ecology and Environmental Science,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266237,China)

机构地区：[1]中国海洋大学海洋生命学院,青岛266003 [2]青岛海洋科学与技术国家实验室海洋生态与环境科学功能实验室,青岛266237

出　　处：《中国科学基金》2018年第5期471-478,共8页Bulletin of National Natural Science Foundation of China

基　　金：国家自然科学基金重大研究计划重点支持项目(批准号:91751202);国家重点研发计划项目(2016YFA0601303)资助

摘　　要：二甲基巯基丙酸内盐(dimethylsulfoniopropionate,DMSP)是地球上最丰富的有机硫分子之一,也是微生物产生"冷室气体"二甲基硫(dimethyl sulfide,DMS)的最主要前体物质,在驱动全球硫循环和调节气候变化中均发挥着重要作用。同时,生物体内的DMSP还可能具有渗透压调节、抗氧化、冷冻保护、硫素贮存等功能。真核生物(主要是浮游植物)一直被认为是DMSP的唯一生产者,然而近期发现有着巨大生物量和活跃代谢能力的海洋α-变形菌纲细菌也可以合成DMSP,这使得异养细菌成为了海洋中DMSP潜在的重要来源。目前已分别从细菌和浮游微藻中鉴定出了一种和两种DMSP合成关键酶的编码基因。此外,海洋细菌还是DMSP的主要分解者,主要通过脱甲基通路(约占DMSP生物降解量的70%,不产生DMS)和裂解通路(约占DMSP生物降解量的30%,产生DMS)实现对DMSP的分解代谢。除细菌外,许多浮游植物和某些真菌也具有裂解DMSP产生DMS的能力。另外,DMSP裂解代谢通路有着很高的物种和遗传多样性,目前已知的DMSP裂解酶多达八种。本文着重对DMSP的生物合成和降解通路中可产生源活性气体DMS的裂解通路及其在硫循环中的作用等方面进行了系统阐述,对深入理解DMSP与DMS的产生机制及生态学效应具有重要科学意义。Dimethylsulfoniopropionate（DMSP）is one of the earth＇s most abundant organosulfur molecules,is believed to be the major precursor of the microbe-generated ＂cooling gas＂,dimethyl sulfide（DMS）,and plays key roles in driving global sulfur cycling and regulating climate change.Meantime,DMSP is predicted to function as an osmoprotectant,a cryoprotectant,an antioxidant and/or a grazing deterrent in its producers.It has long been believed that only marine eukaryotes such as phytoplankton can make DMSP.However,we have recently discovered that marine heterotrophic Alphaproteobacteria,which own huge biomass and active metabolic capability,can also make DMSP,making heterotrophic bacteria be a potential important source of marine DMSP.Until now,one prokaryotic DMSP synthesis enzyme and two eukaryotic DMSP synthesis enzymes have been identified.In addition,marine bacteria are the major catabolisers of DMSP,and phytoplankton and some fungi can also degrade DMSP.Both of them can cleave DMSP and release DMS,but their metabolic pathways are distinct.Until the time of writing,up to eight different DMSP lyases have been identified.This paper systematically illustrates the biosynthesis and cleavage of DMSP and their functions on sulfur cycling,which would have important scientific significance in understanding the mechanism of DMSP and DMS production and their ecological effects.

关 键 词：海洋微生物 二甲基巯基丙酸内盐(DMSP) 二甲基硫(DMS) DMSP生物合成 DMSP裂解 

分 类 号：Q50[生物学—生物化学]