A tetrameric assembly of saposin A: increasing structural diversity in lipid transfer proteins
A tetrameric assembly of saposin A: increasing structural diversity in lipid transfer proteins
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saposin A 的四聚体组装：增加脂质转移蛋白的结构多样性
DOI：
10.1101/2021.08.26.457812
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Shamin M
中科院分区：
文献类型：
--
作者：
Shamin M
皂苷是溶酶体中神经鞘脂脂降解所需的脂转移蛋白。这些小蛋白通过从封闭的单体状态转变为开放的构象来结合脂类，从而暴露出疏水表面，从而结合和保护疏水脂尾免受水环境的影响。皂苷形成一系列多聚体，包围这些结合的脂类，并将它们呈现给溶酶体中的水解酶。人皂苷A的这种脂结合特性已被用来形成适合于膜蛋白结构研究的脂蛋白纳米盘。在这里，我们介绍了一种独特的小鼠皂苷A四聚体组装的晶体结构，该组装是在修改了已发表的制造脂蛋白纳米盘的方案后偶然产生的。这种新的皂苷低聚物的结构突出了这些重要的脂转移蛋白可以采用的三级排列的多样性。
Saposins are lipid transfer proteins required for the degradation of sphingolipids in the lysosome. These small proteins bind lipids by transitioning from a closed, monomeric state to an open conformation exposing a hydrophobic surface that binds and shields hydrophobic lipid tails from the aqueous environment. Saposins form a range of multimeric assemblies to encompass these bound lipids and present them to hydrolases in the lysosome. This lipid-binding property of human saposin A has been exploited to form lipoprotein nanodiscs suitable for structural studies of membrane proteins. Here we present the crystal structure of a unique tetrameric assembly of murine saposin A produced serendipitously, following modifications of published protocols for making lipoprotein nanodiscs. The structure of this new saposin oligomer highlights the diversity of tertiary arrangement that can be adopted by these important lipid transfer proteins.