Ducassou Lionel, Jonasson Gabriella, Dhers Laura, Pietrancosta Nicolas, Ramassamy Booma, Xu-Li Yun, Loriot Marie-Anne, Beaune Philippe, Bertho Gildas, Lombard Murielle, Mansuy Daniel, André François, Boucher Jean-Luc
UMR 8601 CNRS, University Paris Descartes, Paris Sorbonne Cité, 75270 Paris, France.
UMR 9198 CNRS, University Paris Sud, iBiTec-S/SB2SM, CEA Saclay, 91191 Gif sur Yvette, France.
Biochim Biophys Acta. 2015 Jul;1850(7):1426-37. doi: 10.1016/j.bbagen.2015.03.014. Epub 2015 Apr 7.
Cytochrome P450 2U1 (CYP2U1) has been identified from the human genome and is highly conserved in the living kingdom. In humans, it has been found to be predominantly expressed in the thymus and in the brain. CYP2U1 is considered as an "orphan" enzyme as few data are available on its physiological function(s) and active site topology. Its only substrates reported so far were unsaturated fatty acids such as arachidonic acid, and, much more recently, N-arachidonoylserotonin.
We expressed CYP2U1 in yeast Saccharomyces cerevisiae, built a 3D homology model of CYP2U1, screened a library of compounds known to be substrates of CYP2 family with metabolite detection by high performance liquid chromatography-mass spectrometry, and performed docking experiments to explain the observed regioselectivity of the reactions.
We show that drug-related compounds, debrisoquine and terfenadine derivatives, subtrates of CYP2D6 and CYP2J2, are hydroxylated by recombinant CYP2U1 with regioselectivities different from those reported for CYP2D6 and 2J2. Docking experiments of those compounds and of arachidonic acid allow us to explain the regioselectivity of the hydroxylations on the basis of their interactions with key residues of CYP2U1 active site.
Our results show for the first time that human orphan CYP2U1 can oxidize several exogenous molecules including drugs, and describe a first CYP2U1 3D model.
These results could have consequences for the metabolism of drugs particularly in the brain. The described 3D model should be useful to identify other substrates of CYP2U1 and help in understanding its physiologic roles.
细胞色素P450 2U1（CYP2U1）已从人类基因组中鉴定出来，并且在生物界中高度保守。在人类中，已发现它主要在胸腺和大脑中表达。CYP2U1被认为是一种“孤儿”酶，因为关于其生理功能和活性位点拓扑结构的数据很少。到目前为止，其唯一报道的底物是不饱和脂肪酸，如花生四烯酸，以及最近发现的N-花生四烯酰基血清素。
我们在酿酒酵母中表达了CYP2U1，构建了CYP2U1的三维同源模型，通过高效液相色谱-质谱法检测代谢产物，筛选了已知为CYP2家族底物的化合物库，并进行了对接实验以解释观察到的反应区域选择性。
我们表明，与药物相关的化合物、去甲异喹胍和特非那定衍生物，即CYP2D6和CYP2J2的底物，被重组CYP2U1羟基化，其区域选择性与报道的CYP2D6和2J2不同。这些化合物与花生四烯酸的对接实验使我们能够根据它们与CYP2U1活性位点关键残基的相互作用来解释羟基化的区域选择性。
我们的结果首次表明，人类孤儿CYP2U1可以氧化包括药物在内的几种外源性分子，并描述了第一个CYP2U1三维模型。
这些结果可能对药物代谢产生影响，特别是在大脑中。所描述三维模型应有助于识别CYP2U1的其他底物，并有助于理解其生理作用。
