Two radical-dependent mechanisms for anaerobic degradation of the globally abundant organosulfur compound dihydroxypropanesulfonate
作者:Jiayi Liu、Yifeng Wei、Lianyun Lin、Lin Teng、Jinyu Yin、Qiang Lu、Jiawei Chen、Yuchun Zheng、Yaxin Li、Runyao Xu、Weixiang Zhai、Yangping Liu、Yanhong Liu、Peng Cao、Ee Lui Ang、Huimin Zhao、Zhiguang Yuchi、Yan Zhang
DOI:10.1073/pnas.2003434117
日期:2020.7.7
DHPS is also at millimolar levels in highly abundant marine phytoplankton. Its degradation and sulfur recycling by microbes, thus, play important roles in the biogeochemical sulfur cycle. However, DHPS degradative pathways in the anaerobic biosphere are not well understood. Here, we report the discovery and characterization of two O2-sensitive glycyl radical enzymes that use distinct mechanisms for
2(S)-二羟基丙烷磺酸盐(DHPS)是6-脱氧-6-磺基-d-吡喃葡萄糖(磺基奎诺糖)的一种微生物降解产物,该物质是植物硫脂的组成部分,估计年产量为10 10吨。在高度丰富的海洋浮游植物中,DHPS也处于毫摩尔水平。因此,其降解和微生物对硫的再循环在生物地球化学硫循环中起着重要作用。然而,厌氧生物圈中的DHPS降解途径尚不十分清楚。在这里,我们报告两个O 2的发现和表征灵敏的糖基自由基酶,使用不同的机制降解DHPS。DHPS-sulfolyase(HPSG)在硫酸盐和亚硫酸盐还原菌催化C-S裂解以释放亚硫酸盐用作呼吸末端电子受体,产生ħ 2 S. DHPS脱水酶(HpfG),在发酵菌,催化Ç -O裂解生成3-磺基丙醛,随后被NADH依赖性磺基丙醛还原酶(HpfD)还原。这两种酶都存在于包括人类肠道在内的多种环境的细菌中,这表明酶自由基化学对各种厌氧生态位中硫通量的贡献。