School of Environment, Northeast Normal University, No. 2555 Jingyue Avenue, Changchun City, Jilin Province, China.
Jilin Province Water Resources and Hydropower Consultative Company of PR China, Changchun City, Jilin Province, China.
Environ Pollut. 2022 Nov 1;312:120021. doi: 10.1016/j.envpol.2022.120021. Epub 2022 Aug 26.
Steroid estrogens have been detected in oceans, rivers, lakes, groundwaters, soils, and even urban water supply systems, thereby inevitably imposing serious impacts on human health and ecological safety. Indeed, many estrogen-degrading bacterial strains and degradation pathways have been reported, with the 4,5-seco pathway being particularly important. However, few studies have evaluated the use of the 4,5-seco pathway by actinomycetes to degrade 17β-estradiol (E2). In this study, 5 genes involved in E2 degradation were identified in the Rhodococcus equi DSSKP-R-001 (R-001) genome and then heterologously expressed to confirm their functions. The transformation of E2 with hsd17b14 reached 63.7% within 30 h, resulting in transformation into estrone (E1). Furthermore, we found that At1g12200-encoded flavin-binding monooxygenase (FMO) can transform E1 at a rate of 51.6% within 30 h and can transform E1 into 4-hydroxyestrone (4-OH E1). In addition, catA and hsaC genes were identified to further transform 4-OH E1 at a rate of 97-99%, and this reaction was accomplished by C-C cleavage at the C4 position of the A ring of 4-OH E1. This study represents the first report on the roles of these genes in estrogen degradation and provides new insights into the mechanisms of microbial estrogen metabolism and a better understanding of E2 degradation via the 4,5-seco pathway by actinomycetes.
甾体雌激素已在海洋、河流、湖泊、地下水、土壤中被检测到，甚至在城市供水系统中也有存在，这不可避免地对人类健康和生态安全造成了严重影响。事实上，已经报道了许多雌激素降解细菌菌株和降解途径，其中 4,5-断键途径尤为重要。然而，很少有研究评估放线菌利用 4,5-断键途径降解 17β-雌二醇（E2）。在本研究中，从红球菌 DSSKP-R-001（R-001）基因组中鉴定出 5 个与 E2 降解相关的基因，并进行了异源表达以确认其功能。hsd17b14 可在 30 小时内将 E2 转化为 63.7%，转化为雌酮（E1）。此外，我们发现 At1g12200 编码黄素结合单加氧酶（FMO）可以在 30 小时内以 51.6%的速率将 E1 转化为 4-羟基雌酮（4-OH E1）。此外，鉴定出 catA 和 hsaC 基因可进一步将 4-OH E1 以 97-99%的速率转化，该反应通过 C4 位 C-C 断裂完成 A 环的 4-OH E1。本研究首次报道了这些基因在雌激素降解中的作用，为微生物雌激素代谢机制提供了新的见解，并更好地理解了放线菌通过 4,5-断键途径降解 E2。
