Pediatric Endocrinology, Diabetology and Metabolism, University Children's Hospital, Bern, Switzerland.
Biochem Biophys Res Commun. 2011 Sep 9;412(4):572-7. doi: 10.1016/j.bbrc.2011.08.001. Epub 2011 Aug 6.
P450 oxidoreductase (POR) is the electron donor for all microsomal P450s including steroidogenic enzymes CYP17A1, CYP19A1 and CYP21A2. We found a novel POR mutation P399_E401del in two unrelated Turkish patients with 46,XX disorder of sexual development. Recombinant POR proteins were produced in yeast and tested for their ability to support steroid metabolizing P450 activities. In comparison to wild-type POR, the P399_E401del protein was found to decrease catalytic efficiency of 21-hydroxylation of progesterone by 68%, 17α-hydroxylation of progesterone by 76%, 17,20-lyase action on 17OH-pregnenolone by 69%, aromatization of androstenedione by 85% and cytochrome c reduction activity by 80%. Protein structure analysis of the three amino acid deletion P399_E401 revealed reduced stability and flexibility of the mutant. In conclusion, P399_E401del is a novel mutation in POR that provides valuable genotype-phenotype and structure-function correlation for mutations in a different region of POR compared to previous studies. Characterization of P399_E401del provides further insight into specificity of different P450s for interaction with POR as well as nature of metabolic disruptions caused by more pronounced effect on specific P450s like CYP17A1 and aromatase.
细胞色素 P450 氧化还原酶（POR）是所有细胞色素 P450 中的电子供体，包括甾体生成酶 CYP17A1、CYP19A1 和 CYP21A2。我们在两名土耳其非相关的 46,XX 性发育障碍患者中发现了一种新的 POR 突变 P399_E401del。在酵母中产生重组 POR 蛋白，并测试其支持类固醇代谢 P450 活性的能力。与野生型 POR 相比，P399_E401del 蛋白被发现降低了孕酮 21-羟化、孕酮 17α-羟化、17OH-孕烯醇酮 17,20-裂合酶作用、雄烯二酮芳香化和细胞色素 c 还原活性的催化效率分别为 68%、76%、69%、85%和 80%。对三氨基酸缺失 P399_E401 的蛋白结构分析表明，突变体的稳定性和灵活性降低。总之，P399_E401del 是 POR 中的一种新突变，与之前的研究相比，为 POR 不同区域的突变提供了有价值的基因型-表型和结构-功能相关性。对 P399_E401del 的表征提供了进一步的深入了解，了解不同 P450 与 POR 相互作用的特异性以及对特定 P450 如 CYP17A1 和芳香酶的代谢干扰的性质。
