Huang Hui-Yun, Huang Jia-Hua, Wang Yong-Heng, Hu Dan, Lu Yong-Jun, She Zhi-Gang, Chen Guo-Dong, Yao Xin-Sheng, Gao Hao
Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy/Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drugs Research, Jinan University, Guangzhou, China.
School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, China.
Front Chem. 2021 Dec 16;9:785431. doi: 10.3389/fchem.2021.785431. eCollection 2021.
The cytochrome P450 enzymes (P450s or CYPs) are heme-containing enzymes which catalyze a wide range of oxidation reactions in nature. In our previous study, a rare multifunctional P450 AstB was found, which can dually oxidize two methyl groups (C-19 and C-21) of preasperterpenoid A to asperterpenoid A with 3-carboxyl and 11-hydroxymethyl groups. However, the oxidation order of C-19 and C-21 catalyzed by AstB is unclear. In order to reveal this oxidation order, probable pathways catalyzed by AstB were proposed, and the oxidation order of C-19 and C-21 was obtained by quantum chemistry calculations. The potential intermediates (three new asperterpenoids D-F, -) were obtained through the chemical investigation on the extract of the transformant strain and chemical conversions, which were used as the standards to detect their existences in the extract of the transformant strain with HPLC-MS. Combined with the quantum chemistry calculation and the HPLC-MS analysis, the catalyzed order of AstB in asperterpenoid A biosynthesis was revealed. Furthermore, the PTPB inhibition of obtained asperterpenoids was evaluated, and the results showed that 3-carboxyl and the oxidation station of C-21 would be the key factors for PTPB inhibition of asperterpenoids.
细胞色素P450酶（P450s或CYPs）是含血红素的酶，在自然界中催化多种氧化反应。在我们之前的研究中，发现了一种罕见的多功能P450酶AstB，它可以将前曲霉萜A的两个甲基（C-19和C-21）双重氧化为具有3-羧基和11-羟甲基的曲霉萜A。然而，AstB催化C-19和C-21的氧化顺序尚不清楚。为了揭示这种氧化顺序，提出了AstB可能的催化途径，并通过量子化学计算得到了C-19和C-21的氧化顺序。通过对转化菌株提取物的化学研究和化学转化，获得了潜在的中间体（三种新的曲霉萜D-F），并将其用作标准品，通过HPLC-MS检测它们在转化菌株提取物中的存在。结合量子化学计算和HPLC-MS分析，揭示了AstB在曲霉萜A生物合成中的催化顺序。此外，对所得曲霉萜的PTPB抑制作用进行了评估，结果表明3-羧基和C-21的氧化位点是曲霉萜对PTPB抑制作用的关键因素。
