Investigation of the Substrate Range of CYP199A4: Modification of the Partition between Hydroxylation and Desaturation Activities by Substrate and Protein Engineering
作者:Stephen G. Bell、Ruimin Zhou、Wen Yang、Adrian B. H. Tan、Alexander S. Gentleman、Luet-Lok Wong、Weihong Zhou
DOI:10.1002/chem.201202776
日期:2012.12.21
enzyme CYP199A4, from Rhodopseudomonas palustris HaA2, can efficiently demethylate 4‐methoxybenzoic acid. It is also capable of oxidising a range of other related substrates. By investigating substrates with different substituents and ring systems we have been able to show that the carboxylate group and the nature of the ring system and the substituent are all important for optimal substrate binding
细胞色素P450酶CYP199A4,来自Phodopseudomonas palustrisHaA2可以有效地使4-甲氧基苯甲酸去甲基化。它还能够氧化多种其他相关的底物。通过研究具有不同取代基和环系统的底物,我们已经能够证明羧酸酯基团以及环系统和取代基的性质对于优化底物结合和活性都至关重要。藜芦酸,2-萘甲酸和吲哚-6-羧酸底物结合的CYP199A4复合物的结构揭示了底物的结合模式和活性位点残基的侧链构象变化,以适应这些较大的底物。它们还为产物氧化的选择性提供了理论依据。CYP199A4对烷基取代的苯甲酸的氧化更复杂,去饱和反应与羟基化活性竞争。β Ç 乙基的H键更靠近血红素铁比作为C α(3.5对4.8)。当与反应中间体的相对能量耦合时,该观察结果表明烷基相对于血红素铁的定位对于确定所观察到的去饱和量可能是至关重要的。通过突变CYP199A4(Phe185)活性位点中的单个残基,我们能够将该酶转化为4-乙基苯甲酸去饱和酶。