Brown Christian, Patrick Joan, Liebau Jobst, Mäler Lena
Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden.
Biochem Biophys Rep. 2022 Feb 10;30:101229. doi: 10.1016/j.bbrep.2022.101229. eCollection 2022 Jul.
Chitin synthases are vital for growth in certain oomycetes as chitin is an essential component in the cell wall of these species. In , two chitin synthases have been found, and both contain a Microtubule Interacting and Trafficking (MIT) domain. The MIT domain has been implicated in lipid interaction, which in turn may be of significance for targeting of chitin synthases to the plasma membrane. In this work we have investigated the lipid interacting properties of the MIT domain from chitin synthase 1 in . We show by fluorescence spectroscopy techniques that the MIT domain interacts preferentially with phosphatidic acid (PA), while it does not interact with phosphatidylglycerol (PG) or phosphatidylcholine (PC). These results strongly suggest that the specific properties of PA are required for membrane interaction of the MIT domain. PA is negatively charged, binds basic side chains with high affinity and its small headgroup gives rise to membrane packing defects that enable intercalation of hydrophobic amino acids. We propose a mode of lipid interaction that involves a combination of basic amino acid residues and Trp residues that anchor the MIT domain specifically to bilayers that contain PA.
几丁质合成酶对于某些卵菌纲生物的生长至关重要，因为几丁质是这些物种细胞壁的重要组成部分。在[具体物种名称未给出]中，已发现两种几丁质合成酶，且二者均含有微管相互作用与运输（MIT）结构域。MIT结构域与脂质相互作用有关，这反过来可能对于几丁质合成酶靶向质膜具有重要意义。在这项工作中，我们研究了来自[具体物种名称未给出]几丁质合成酶1的MIT结构域的脂质相互作用特性。我们通过荧光光谱技术表明，MIT结构域优先与磷脂酸（PA）相互作用，而不与磷脂酰甘油（PG）或磷脂酰胆碱（PC）相互作用。这些结果强烈表明，PA的特定特性是MIT结构域与膜相互作用所必需的。PA带负电荷，以高亲和力结合碱性侧链，其小的头部基团会导致膜堆积缺陷，从而使疏水性氨基酸能够插入。我们提出了一种脂质相互作用模式，该模式涉及碱性氨基酸残基和色氨酸残基的组合，这些残基将MIT结构域特异性地锚定到含有PA的双层膜上。
