Modulation of non-bilayer lipid phases and the structure and functions of thylakoid membranes: effects on the water-soluble enzyme violaxanthin de-epoxidase
Modulation of non-bilayer lipid phases and the structure and functions of thylakoid membranes: effects on the water-soluble enzyme violaxanthin de-epoxidase
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DOI：
10.1038/s41598-020-68854-x
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发表时间：
2020-07-20
影响因子：
4.6
通讯作者：
Garab, Gyozo
中科院分区：
文献类型：
--
作者：
Dlouhy, Ondrej;Kurasova, Irena;Garab, Gyozo
非双层脂质和非板层脂相在生物膜中的作用是膜生物学的一个谜。非双层脂质大量存在于所有膜中;在能量转换膜中，它们占总脂质含量的一半左右，但它们的功能状态是双层。体外实验表明，植物类囊体的水溶性紫黄质脱环氧酶（VDE）的功能需要一个非双层脂相的存在。P-31-NMR光谱为功能性类囊体膜中的脂质多态性提供了证据。在这里，我们揭示了可逆的pH值和温度依赖性的变化的脂质相的行为，特别是各向同性的非层状相的灵活性，孤立的菠菜类囊体。这些重组伴随着膜的渗透性和热力学参数的变化，并出现控制VDE的活性和叶绿素-a荧光的非光化学猝灭的光保护机制。这些数据表明，第一次在天然膜中，由非双层脂质相的水溶性酶的活性的调制。
The role of non-bilayer lipids and non-lamellar lipid phases in biological membranes is an enigmatic problem of membrane biology. Non-bilayer lipids are present in large amounts in all membranes; in energy-converting membranes they constitute about half of their total lipid content-yet their functional state is a bilayer. In vitro experiments revealed that the functioning of the water-soluble violaxanthin de-epoxidase (VDE) enzyme of plant thylakoids requires the presence of a non-bilayer lipid phase. P-31-NMR spectroscopy has provided evidence on lipid polymorphism in functional thylakoid membranes. Here we reveal reversible pH- and temperature-dependent changes of the lipid-phase behaviour, particularly the flexibility of isotropic non-lamellar phases, of isolated spinach thylakoids. These reorganizations are accompanied by changes in the permeability and thermodynamic parameters of the membranes and appear to control the activity of VDE and the photoprotective mechanism of non-photochemical quenching of chlorophyll-a fluorescence. The data demonstrate, for the first time in native membranes, the modulation of the activity of a water-soluble enzyme by a non-bilayer lipid phase.