Chemometric Analysis of Bacterial Peptidoglycan Reveals Atypical Modifications That Empower the Cell Wall against Predatory Enzymes and Fly Innate Immunity
Chemometric Analysis of Bacterial Peptidoglycan Reveals Atypical Modifications That Empower the Cell Wall against Predatory Enzymes and Fly Innate Immunity
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DOI：
10.1021/jacs.6b04430
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发表时间：
2016-07-27
影响因子：
15
通讯作者：
Cava, Felipe
中科院分区：
文献类型：
--
作者：
Espaillat, Akbar;Forsmo, Oskar;Cava, Felipe
肽聚糖是大多数细菌的基本结构。它有助于细胞形态，并提供抵抗环境侮辱的细胞壁完整性。虽然有几项研究已经报道了细菌中肽聚糖的化学组成和组织存在很大程度的变异性，但这种聚合物的真正多样性还远未得到充分探索。这项工作利用快速超高效液相色谱和多元数据分析来揭示α蛋白细菌纲的肽聚糖化学多样性，这是一组在新陈代谢、形态和生活方式方面高度异质性的革兰氏阴性细菌。事实上，化学计量学分析揭示了醋酸杆菌中保守的新的肽多糖结构：中位二氨基戊二酸的α-(L)-羧基上的酰胺化，以及(1-3)L-丙氨酸-D-(中位)二胺基戊二酸交联物的存在。这两种结构都是生长控制的修饰，影响对VI型分泌系统肽聚糖内肽酶的敏感性和果蝇天然免疫系统的识别，表明这些细菌在环境适应中发挥了相关作用。总而言之，我们的发现证明了化学计量学工具在大型细胞壁层析数据集上发现细菌中新的肽聚糖结构特性的辨别能力。
Peptidoglycan is a fundamental structure for most bacteria. It contributes to the cell morphology and provides cell wall integrity against environmental insults. While several studies have reported a significant degree of variability in the chemical composition and organization of peptidoglycan in the domain Bacteria, the real diversity of this polymer is far from fully explored. This work exploits rapid ultraperformance liquid chromatography and multivariate data analysis to uncover peptidoglycan chemical diversity in the Class Alphaproteobacteria, a group of Gram negative bacteria that are highly heterogeneous in terms of metabolism, morphology and life-styles. Indeed, chemometric analyses revealed novel peptidoglycan structures conserved in Acetobacteria: amidation at the alpha-(L)-carboxyl of meso-diaminopimelic acid and the presence of muropeptides cross-linked by (1-3) L-Ala-D-(meso)diaminopimelate cross-links. Both structures are growth-controlled modifications that influence sensitivity to Type VI secretion system peptidoglycan endopeptidases and recognition by the Drosophila innate immune system, suggesting relevant roles in the environmental adaptability of these bacteria. Collectively our findings demonstrate the discriminative power of chemometric tools on large cell wall-chromatographic data sets to discover novel peptidoglycan structural properties in bacteria.