Ionic Environment Affects Bacterial Lipopolysaccharide Packing and Function
Ionic Environment Affects Bacterial Lipopolysaccharide Packing and Function
复制标题
离子环境影响细菌脂多糖的堆积和功能
DOI：
10.1021/acs.langmuir.9b03162
复制
发表时间：
2020
期刊：
影响因子：
3.9
通讯作者：
Hernandez, Rigoberto
中科院分区：
文献类型：
--
作者：
Rahnamoun, Ali;Kim, Kyoungtea;Pedersen, Joel A.;Hernandez, Rigoberto
脂多糖（LPS）与金属离子的相互作用强烈影响革兰氏阴性菌外膜的稳定性和功能。深粗糙（Re）LPS包装和功能的离子环境的敏感性，阳离子价和离子半径的影响，已确定使用分子动力学模拟和朗缪尔平衡实验。通过测量在平衡结束时投影到界面平面上的每个LPS分子的有效平均分子面积（A μ m）来评估在不同阳离子存在下LPS模型内的LPS聚集程度。将这些结果与来自实验测量的LPS平均分子面积进行比较，其中使用朗缪尔膜天平在空气-水界面处组装LPS单层。我们发现，包装的LPS阵列是敏感的离子半径和离子价存在于溶液中的阳离子在LPS阵列包装。使用增强的采样的自由能为嵌入的oligo（烯丙胺盐酸盐）（OAH）到深粗糙沙门氏菌entericaLPS双层，我们得到的亲合力的核心部分的LPS OAH作为一个功能的性质的金属阳离子存在于溶液中。我们发现溶剂化LPS双层模型的填充对中和阳离子的离子半径和离子价态敏感。这进一步表明，离子桥和空间位阻而不是电荷屏蔽是在低离子浓度条件下减轻配体嵌入的重要因素。
The interaction of lipopolysaccharides (LPS) with metal cations strongly affects the stability and function of the Gram-negative bacterial outer membrane. The sensitivity of deep rough (Re) LPS packing and function to the ionic environment, as affected by cation valency and ionic radius, has been determined using molecular dynamics simulations and Langmuir balance experiments. The degree of LPS aggregation within the LPS models in the presence of different cations is assessed by measuring the effective mean molecular area (Âm) of each LPS molecule projected onto the interfacial plane at the end of the equilibration. These results are compared to the LPS mean molecular area from experimental measurements in which the LPS monolayers are assembled at the air–water interface using a Langmuir film balance. We found that packing of the LPS arrays is sensitive to the ionic radius and ion valency of the cations present in solution during LPS array packing. Using enhanced sampling of the free energy for the intercalation of oligo(allylamine HCl) (OAH) into deep roughSalmonella entericaLPS bilayers, we obtained the affinity of the core section of LPS to OAH as a function of the nature of the metal cations present in solution. We found that packing of the solvated LPS bilayer models is sensitive to ionic radius and ion valency of the neutralizing cations. This further suggests that ion bridging and steric barriers rather than charge shielding are important factors in mitigating ligand intercalation under conditions with low ionic concentrations.