Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland.
Biocenter Oulu, University of Oulu, Oulu, Finland.
Nat Commun. 2023 Feb 4;14(1):619. doi: 10.1038/s41467-023-36358-7.
Mitochondrial fatty acid synthesis (mtFAS) is essential for respiratory function. MtFAS generates the octanoic acid precursor for lipoic acid synthesis, but the role of longer fatty acid products has remained unclear. The structurally well-characterized component of mtFAS, human 2E-enoyl-ACP reductase (MECR) rescues respiratory growth and lipoylation defects of a Saccharomyces cerevisiae Δetr1 strain lacking native mtFAS enoyl reductase. To address the role of longer products of mtFAS, we employed in silico molecular simulations to design a MECR variant with a shortened substrate binding cavity. Our in vitro and in vivo analyses indicate that the MECR G165Q variant allows synthesis of octanoyl groups but not long chain fatty acids, confirming the validity of our computational approach to engineer substrate length specificity. Furthermore, our data imply that restoring lipoylation in mtFAS deficient yeast strains is not sufficient to support respiration and that long chain acyl-ACPs generated by mtFAS are required for mitochondrial function.
线粒体脂肪酸合成（mtFAS）对于呼吸功能至关重要。MtFAS 生成用于硫辛酸合成的辛酸前体，但较长脂肪酸产物的作用仍不清楚。mtFAS 的结构特征良好的组成部分，人 2E-烯酰-ACP 还原酶（MECR）挽救了呼吸生长和缺乏天然 mtFAS 烯酰还原酶的酿酒酵母Δetr1 菌株的硫脂酰化缺陷。为了解决 mtFAS 较长产物的作用，我们采用计算机分子模拟设计了一种具有缩短的底物结合腔的 MECR 变体。我们的体外和体内分析表明，MECR G165Q 变体允许合成辛酰基，但不能合成长链脂肪酸，这证实了我们用于工程化底物长度特异性的计算方法的有效性。此外，我们的数据表明，在 mtFAS 缺陷酵母菌株中恢复硫脂酰化不足以支持呼吸，并且 mtFAS 产生的长链酰基-ACP 对于线粒体功能是必需的。
