M.M. Shemyakin & Yu.A. Ovchinnikov Institute of Bioorganic Chemistry, the Russian Academy of Sciences, 117997 Moscow, Russia.
Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia.
Biomolecules. 2023 Nov 24;13(12):1699. doi: 10.3390/biom13121699.
Lipid transfer proteins (LTPs) realize their functions in plants due to their ability to bind and transport various ligands. Structures of many LTPs have been studied; however, the mechanism of ligand binding and transport is still not fully understood. In this work, we studied the role of Lys61 and Lys81 located near the "top" and "bottom" entrances to the hydrophobic cavity of the lentil lipid transfer protein Lc-LTP2, respectively, in these processes. Using site-directed mutagenesis, we showed that both amino acid residues played a key role in lipid binding to the protein. In experiments with calcein-loaded liposomes, we demonstrated that both the above-mentioned lysine residues participated in the protein interaction with model membranes. According to data obtained from fluorescent spectroscopy and TNS probe displacement, both amino acid residues are necessary for the ability of the protein to transfer lipids between membranes. Thus, we hypothesized that basic amino acid residues located at opposite entrances to the hydrophobic cavity of the lentil Lc-LTP2 played an important role in initial protein-ligand interaction in solution as well as in protein-membrane docking.
脂质转移蛋白（LTPs）因其能够结合和转运各种配体而在植物中发挥作用。许多 LTPs 的结构已经得到研究；然而，配体结合和转运的机制仍不完全清楚。在这项工作中，我们研究了位于菜豆脂质转移蛋白 Lc-LTP2 疏水腔“顶部”和“底部”入口附近的 Lys61 和 Lys81 氨基酸残基在这些过程中的作用。通过定点突变，我们表明这两个氨基酸残基在脂质与蛋白质的结合中都发挥了关键作用。在含有钙黄绿素的脂质体实验中，我们证明了上述两个赖氨酸残基都参与了蛋白质与模型膜的相互作用。根据荧光光谱和 TNS 探针置换获得的数据，这两个氨基酸残基对于蛋白质在膜之间转移脂质的能力都是必需的。因此，我们假设位于菜豆 Lc-LTP2 疏水腔相对入口处的碱性氨基酸残基在溶液中以及在蛋白质-膜对接过程中，在初始蛋白质-配体相互作用中发挥了重要作用。
