Abstract The genome of Sphingobium yanoikuyae YC-XJ2 with aryl organophosphorus flame retardants (aryl-OPFRs) degrading activity was sequenced and analyzed systematically. The gene sy-pte was cloned and expressed, and the molecular mechanism of aryl-OPFRs degradation was elucidated. Sy-PTE exhibited enzymatic properties of alkali, high temperature and salt resistance. The hydrolyzation of EHDPP by phosphotriesterase was first reported. The specific activity of Sy-PTE was 67.0 ± 1.4 (U mg−1) for TPhP with kcat/Km and Vmax values of 4.8 ± 0.6 × 103 (mM−1·s−1) and 0.29 ± 0.02 (μM·s−1), Km of 15.6 ± 0.34 (μM), kcat of 75.02 ± 1.5 s−1, and need no metal ion activator to assist. The structural comparison of the metal binding sites with Sb-PTE (PDB ID 5HRM ) showed that the transition from uncharged Met-259 to positively charged Asn-259 in Sy-PET might affect the binding of Mn2+ to His-258 because of the same electrical properties, and the transition from Gly-473 without side chains in Sb-PTE to Ala-473 might cause steric hindrance in binding of Mn2+ to His-475. Based on enzymatic advantages, Sy-PTE should be a promising engineered enzyme in the future for bioremediation of aryl-OPFRs polluted sites.

中文翻译：

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芳基有机磷阻燃剂降解能力及相关磷酸三酯酶特性的耐盐Sphingobium yanoikuyae YC-XJ2基因组分析

摘要 对具有芳基有机磷阻燃剂(aryl-OPFRs)降解活性的Sphingobium yanoikuyae YC-XJ2基因组进行了系统测序和分析。克隆并表达了sy-pte基因，阐明了芳基OPFRs降解的分子机制。Sy-PTE表现出耐碱、耐高温和耐盐的酶学性质。首次报道了磷酸三酯酶对 EHDPP 的水解。Sy-PTE 对 TPhP 的比活性为 67.0 ± 1.4 (U mg-1)，kcat/Km 和 Vmax 值为 4.8 ± 0.6 × 103 (mM-1·s-1) 和 0.29 ± 0.02 (μM·s- 1)，Km 为 15.6 ± 0.34 (μM)，kcat 为 75.02 ± 1.5 s−1，并且不需要金属离子活化剂来辅助。金属结合位点与 Sb-PTE (PDB ID 5HRM ) 的结构比较表明 Sy-PET 中从不带电的 Met-259 到带正电的 Asn-259 的转变可能会影响 Mn2+ 与 His-258 的结合，因为相同电性质，并且从 Sb-PTE 中没有侧链的 Gly-473 过渡到 Ala-473 可能会导致 Mn2+ 与 His-475 结合的空间位阻。基于酶学优势，Sy-PTE 应该是未来用于芳基 OPFRs 污染位点生物修复的有前途的工程酶。