Dynamics Characterization of Fully Hydrated Bacterial Cell Walls by Solid-State NMR: Evidence for Cooperative Binding of Metal Ions
Dynamics Characterization of Fully Hydrated Bacterial Cell Walls by Solid-State NMR: Evidence for Cooperative Binding of Metal Ions
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DOI：
10.1021/ja104533w
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发表时间：
2010-08-11
影响因子：
15
通讯作者：
Simorre, Jean-Pierre
中科院分区：
文献类型：
--
作者：
Kern, Thomas;Giffard, Mathilde;Simorre, Jean-Pierre
细菌细胞壁维持细胞的完整性，同时允许生长和分裂。它由肽聚糖(PG)组成，这是一种形成几千亿吨袋状结构的生物聚合物，此外，在革兰氏阳性细菌中，它还由共价连接的阴离子聚合物组成，统称为磷壁酸。这些阴离子聚合物被认为在宿主细胞黏附、炎症和免疫激活中发挥重要作用。在这篇文章中，我们使用魔角样品旋转(MAS)的固体核磁共振波谱技术，比较了来自革兰氏阴性菌和不同革兰氏阳性菌的肽聚糖的柔韧性和结构。核磁共振指纹图谱表明，所有这些细菌物种中的PG都有相同的局部构象。从大肠杆菌到枯草杆菌，从枯草杆菌到金黄色葡萄球菌，肽多聚糖网络中的动力学降低，并且主要与多肽的交联度有关。对于完整的细菌细胞和分离的细胞壁，我们发现P-31固体核磁共振特别适合于表征和区分不同物种的壁磷壁酸。我们进一步观察到与二价离子的络合作用，突出了革兰氏阳性细胞壁结构的一个重要结构方面。我们提出了一个新的模型来研究二价阳离子与壁磷壁酸和肽聚糖的羰基的相互作用。
The bacterial cell wall maintains a cell's integrity while allowing growth and division. It is made up of peptidoglycan (PG), a biopolymer forming a multigigadalton bag-like structure, and, additionally in Gram-positive bacteria, of covalently linked anionic polymers collectively called teichoic acids. These anionic polymers are thought to play important roles in host-cell adhesion, inflammation, and immune activation. In this Article, we compare the flexibility and the organization of peptidoglycans from Gram-negative bacteria (E. coli) with its counterpart from different Gram-positive bacteria using solid-state nuclear magnetic resonance spectroscopy (NMR) under magic-angle sample spinning (MAS). The NMR fingerprints suggest an identical local conformation of the PG in all of these bacterial species. Dynamics in the peptidoglycan network decreases from E. coli to B. subtilis and from B. subtilis to S. aureus and correlates mainly with the degree of peptide cross-linkage. For intact bacterial cells and isolated cell walls, we show that P-31 solid-state NMR is particularly well adapted to characterize and differentiate wall teichoic acids of different species. We have further observed complexation with divalent ions, highlighting an important structural aspect of Gram-positive cell wall architecture. We propose a new model for the interaction of divalent cations with both wall teichoic acids and carbonyl groups of peptidoglycan.