Fokina Victoria, Lobastova Tatyana, Tarlachkov Sergey, Shutov Andrei, Kazantsev Alexey, Donova Marina
Skryabin Institute of Biochemistry and Physiology of Microorganisms RAS, Federal Research Center "Pushchino Center for Biological Research of the Russian Academy of Sciences", Pr. Nauki 5, Pushchino, Moscow Region, 142290, Russian Federation.
Chemistry Department, Lomonosov Moscow State University, Leninskie Gory 1/3, Moscow, 119991, Russian Federation.
Curr Microbiol. 2025 Feb 19;82(4):143. doi: 10.1007/s00284-025-04105-4.
Molecular mechanisms of C-steroid core degradation have been intensively studied mostly in mycolic acid rich actinobacteria, mainly in the representatives of Mycobacterium, Mycolicibacterium and Rhodococcus genera, whilst much less data evidencing functionality of the 9(10)-seco pathway in other actinobacteria was reported. In this study, degradation of androstenedione (AD), androstadienedione (ADD), testosterone (T), Δ-dehydrotestosterone (DT) and 9α-hydroxyandrostenedione (9α-OH-AD) by the biotechnologically relevant actinobacterium of Nocardioides simplex VKM Ac-2033D was investigated. Key intermediates of 9α-OH-AD degradation were isolated and identified as 3-hydroxy-9,10-seco-androsta-1,3,5(10)-triene-9,17-dione (3-HSA) and 3,17β-dihydroxy-9,10-seco-androsta-1,3,5(10)-trien-9-one (3,17-DHSA). The structures of the compounds were confirmed by MS, H- and C-NMR. Differential gene expression on medium with glycerol and yeast extract with and without AD addition was estimated. The expression of two sets of the genes related to the 9(10)-seco pathway was increased in the presence of AD. One set comprised the genes from the KstR2-regulons in the clusters A and C, while another set included the genes without the binding sites for KstR/KstR2 (Cluster D). These genes putatively encoded 3-oxosteroid-Δ-dehydrogenase and 3-oxosteroid 9α-hydroxylase, as well as a group of enzymes dealing with the ring B opening (HsaA3, HsaB3, HsaC3 and HsaD3). Process of degradation of exogenous C-steroids in N. simplex proceeds via the 9(10)-seco pathway and can be controlled not only by KstR2 regulator, but also by other transcriptional factors. The results contribute to the knowledge on steroid core degradation in actinobacteria and are of significance at the development of methods for production of valuable indane compounds.
C-甾体核心降解的分子机制主要在富含分枝菌酸的放线菌中进行了深入研究，主要是在分枝杆菌属、分枝杆菌属和红球菌属的代表菌株中，而关于9(10)-开环途径在其他放线菌中的功能的数据报道较少。在本研究中，对生物技术相关的简单诺卡氏菌VKM Ac-2033D降解雄烯二酮（AD）、雄二烯二酮（ADD）、睾酮（T）、Δ-脱氢睾酮（DT）和9α-羟基雄烯二酮（9α-OH-AD）进行了研究。分离并鉴定了9α-OH-AD降解的关键中间体为3-羟基-9,10-开环-雄甾-1,3,5(10)-三烯-9,17-二酮（3-HSA）和3,17β-二羟基-9,10-开环-雄甾-1,3,5(10)-三烯-9-酮（3,17-DHSA）。通过质谱、氢谱和碳谱确认了化合物的结构。评估了在添加和不添加AD的甘油和酵母提取物培养基上的差异基因表达。在AD存在的情况下，与9(10)-开环途径相关的两组基因的表达增加。一组包括来自簇A和C中KstR2调控子的基因，而另一组包括没有KstR/KstR2结合位点的基因（簇D）。这些基因推测编码3-氧代甾体-Δ-脱氢酶和3-氧代甾体9α-羟化酶，以及一组处理B环开环的酶（HsaA3、HsaB3、HsaC3和HsaD3）。简单诺卡氏菌中外源C-甾体的降解过程通过9(10)-开环途径进行，不仅可以由KstR2调节因子控制，还可以由其他转录因子控制。这些结果有助于了解放线菌中甾体核心的降解，对开发生产有价值的茚化合物的方法具有重要意义。
