Structural determinants of lipid specificity within Ups/PRELI lipid transfer proteins
Structural determinants of lipid specificity within Ups/PRELI lipid transfer proteins
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DOI：
10.1038/s41467-019-09089-x
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发表时间：
2019-03-08
影响因子：
16.6
通讯作者：
Langer, Thomas
中科院分区：
文献类型：
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作者：
Miliara, Xeni;Tatsuta, Takashi;Langer, Thomas
Ups/PRELI家族的保守脂质转移蛋白通过以脂质特异性方式穿梭于膜间隙来调节线粒体中的脂质积累。在这里，我们结合联合收割机结构分析，无偏见的遗传方法在酵母和分子动力学模拟解开保守的UPS/PRELI家族内的脂质特异性的决定因素。我们提出了人PRELID 1-TRIAP 1和PRELID 3b-TRIAP 1复合物的结构，它们分别对磷脂酸和磷脂酰丝氨酸发挥脂质转移活性。反向酵母基因筛选确定关键氨基酸交换，扩大和交换他们的脂质特异性。我们发现，参与头基识别和疏水性的柔性环调节脂质进入结合腔的氨基酸。分子动力学模拟揭示了不同的膜取向的PRELID 1和PRELID 3b在逐步释放的脂质。因此，我们的实验定义了脂质特异性的结构决定因素和Ups/PRELI蛋白的脂质相互作用的动力学。
Conserved lipid transfer proteins of the Ups/PRELI family regulate lipid accumulation in mitochondria by shuttling phospholipids in a lipid-specific manner across the intermembrane space. Here, we combine structural analysis, unbiased genetic approaches in yeast and molecular dynamics simulations to unravel determinants of lipid specificity within the conserved Ups/PRELI family. We present structures of human PRELID1-TRIAP1 and PRELID3b-TRIAP1 complexes, which exert lipid transfer activity for phosphatidic acid and phosphatidylserine, respectively. Reverse yeast genetic screens identify critical amino acid exchanges that broaden and swap their lipid specificities. We find that amino acids involved in head group recognition and the hydrophobicity of flexible loops regulate lipid entry into the binding cavity. Molecular dynamics simulations reveal different membrane orientations of PRELID1 and PRELID3b during the stepwise release of lipids. Our experiments thus define the structural determinants of lipid specificity and the dynamics of lipid interactions by Ups/PRELI proteins.