Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA.
Mass Spectrometry Resource, Division of Endocrinology, Diabetes, Metabolism, and Lipid Research, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
Int J Mol Sci. 2024 Oct 10;25(20):10908. doi: 10.3390/ijms252010908.
Sterol biosynthesis requires the oxidative removal of two methyl groups from the C-4 position by sterol C-4-demethylase and one methyl group from the C-14 position by sterol C-14-demethylase. In , a CYP5122A1 (Cytochrome P450 family 5122A1) protein was recently identified as the bona fide sterol C-4 methyl oxidase catalyzing the initial steps of C-4-demethylation. Besides CYP5122A1, parasites possess orthologs to ERG25 (ergosterol pathway gene 25), the canonical sterol C-4 methyl oxidase in . To determine the contribution of and in sterol biosynthesis, we assessed the essentiality of these genes in , which causes cutaneous leishmaniasis. Like in , in could only be deleted in the presence of a complementing episome. Even with strong negative selection, chromosomal -null mutants retained the complementing episome in both promastigote and amastigote stages, demonstrating its essentiality. In contrast, the -null mutants were fully viable and replicative in culture and virulent in mice. Deletion and overexpression of ERG25 did not affect the sterol composition, indicating that ERG25 is not required for C-4-demethylation. These findings suggest that CYP5122A1 is the dominant and possibly only sterol C-4 methyl oxidase in , and inhibitors of CYP5122A1 may have strong therapeutic potential against multiple species.
甾醇生物合成需要甾醇 C-4 脱甲基酶从 C-4 位氧化去除两个甲基，甾醇 C-14 脱甲基酶从 C-14 位去除一个甲基。最近在 中鉴定出一种 CYP5122A1（细胞色素 P450 家族 5122A1）蛋白，它是真正的甾醇 C-4 甲基氧化酶，催化 C-4 脱甲基的初始步骤。除了 CYP5122A1， 寄生虫还拥有与 ERG25（甾醇途径基因 25）的同源物，这是 在中的典型甾醇 C-4 甲基氧化酶。为了确定 和 在甾醇生物合成中的贡献，我们评估了这些基因在 中的必要性， 引起皮肤利什曼病。与 在 中一样， 只能在存在互补附加体的情况下被删除。即使有强烈的负选择， 在 中的染色体 -null 突变体在裂殖体和无鞭毛体阶段都保留了互补的附加体，证明了其必要性。相比之下，-null 突变体在培养物中完全具有活力和复制能力，并且在小鼠中具有毒力。ERG25 的缺失和过表达都不会影响甾醇组成，表明 ERG25 不需要 C-4 脱甲基。这些发现表明 CYP5122A1 是 在中的主要且可能是唯一的甾醇 C-4 甲基氧化酶，CYP5122A1 的抑制剂可能对多种 物种具有很强的治疗潜力。
