Conformational dynamics of the membrane enzyme LspA upon antibiotic and substrate binding
Conformational dynamics of the membrane enzyme LspA upon antibiotic and substrate binding
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DOI：
10.1016/j.bpj.2022.04.038
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发表时间：
2022-06-07
影响因子：
3.4
通讯作者：
Columbus, Linda
中科院分区：
文献类型：
--
作者：
Caldwell, Tracy A.;Vickery, Owen N.;Columbus, Linda
脂蛋白信号肽酶 (LspA) 是一种天冬氨酰蛋白酶，作为脂蛋白加工途径的一部分，可裂解脂蛋白的跨膜螺旋信号肽。该途径的成员是抗生素疗法开发的极好靶标，因为它们对于革兰氏阴性菌是必需的，对于革兰氏阳性菌的毒力也很重要，并且可能不会产生抗生素耐药性。在这里，我们报告了 LspA 在 apo 状态下的构象动力学，并使用分子动力学模拟和电子顺磁共振确定了与抗生素球霉素的结合。周质螺旋在纳秒时间尺度上波动，并在不同状态下采样独特的构象。在apo状态下，主要构象是最封闭的，并遮挡脂质双层的带电活性位点。与抗生素结合时，存在多种结合模式，周质螺旋的主要构象处于更开放的构象中。在结合态和载脂蛋白态中观察到的不同构象表明了灵活且适应性强的活性位点，这解释了 LspA 如何适应和处理如此多种底物。
Lipoprotein signal peptidase (LspA) is an aspartyl protease that cleaves the transmembrane helix signal peptide of lipoproteins as part of the lipoprotein-processing pathway. Members of this pathway are excellent targets for the development of antibiotic therapeutics because they are essential in Gram-negative bacteria, are important for virulence in Gram-positive bac-teria, and may not develop antibiotic resistance. Here, we report the conformational dynamics of LspA in the apo state and bound to the antibiotic globomycin determined using molecular dynamics simulations and electron paramagnetic resonance. The peri-plasmic helix fluctuates on the nanosecond timescale and samples unique conformations in the different states. In the apo state, the dominant conformation is the most closed and occludes the charged active site from the lipid bilayer. With antibiotic bound there are multiple binding modes with the dominant conformation of the periplasmic helix in a more open conformation. The different conformations observed in both bound and apo states indicate a flexible and adaptable active site, which explains how LspA accommodates and processes such a variety of substrates.