State Key Lab of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China.
College of Marine Life Sciences, Ocean University of China, Qingdao, China.
Elife. 2021 May 10;10:e64045. doi: 10.7554/eLife.64045.
Dimethylsulfoniopropionate (DMSP) is an abundant and ubiquitous organosulfur molecule in marine environments with important roles in global sulfur and nutrient cycling. Diverse DMSP lyases in some algae, bacteria, and fungi cleave DMSP to yield gaseous dimethyl sulfide (DMS), an infochemical with important roles in atmospheric chemistry. Here, we identified a novel ATP-dependent DMSP lyase, DddX. DddX belongs to the acyl-CoA synthetase superfamily and is distinct from the eight other known DMSP lyases. DddX catalyses the conversion of DMSP to DMS via a two-step reaction: the ligation of DMSP with CoA to form the intermediate DMSP-CoA, which is then cleaved to DMS and acryloyl-CoA. The novel catalytic mechanism was elucidated by structural and biochemical analyses. DddX is found in several Alphaproteobacteria, Gammaproteobacteria, and Firmicutes, suggesting that this new DMSP lyase may play an overlooked role in DMSP/DMS cycles.
二甲基巯基丙酸酯（DMSP）是海洋环境中一种丰富且普遍存在的有机硫分子，在全球硫和养分循环中具有重要作用。一些藻类、细菌和真菌中的多种 DMSP 裂解酶将 DMSP 裂解为气态二甲基硫（DMS），DMS 是一种在大气化学中具有重要作用的信息素。在这里，我们鉴定了一种新型的依赖于 ATP 的 DMSP 裂解酶，DddX。DddX 属于酰基辅酶 A 合成酶超家族，与其他已知的 8 种 DMSP 裂解酶不同。DddX 通过两步反应催化 DMSP 转化为 DMS：DMSP 与 CoA 的连接形成中间产物 DMSP-CoA，然后 DMSP-CoA 裂解为 DMS 和丙烯酰基辅酶 A。通过结构和生化分析阐明了新颖的催化机制。DddX 存在于几种α变形菌、γ变形菌和厚壁菌中，这表明这种新的 DMSP 裂解酶可能在 DMSP/DMS 循环中发挥了被忽视的作用。
