Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States.
Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30602, United States.
Anal Chem. 2020 Jul 7;92(13):9146-9155. doi: 10.1021/acs.analchem.0c01449. Epub 2020 Jun 16.
Glycerophospholipids (GPLs), one of the main components of bacterial cell membranes, exhibit high levels of structural complexity that are directly correlated with biophysical membrane properties such as permeability and fluidity. This structural complexity arises from the substantial variability in the individual GPL structural components such as the acyl chain length and headgroup type and is further amplified by the presence of modifications such as double bonds and cyclopropane rings. Here we use liquid chromatography coupled to high-resolution and high-mass-accuracy ultraviolet photodissociation mass spectrometry for the most in-depth study of bacterial GPL modifications to date. In doing so, we unravel a diverse array of unexplored GPL modifications, ranging from acyl chain hydroxyl groups to novel headgroup structures. Along with characterizing these modifications, we elucidate general trends in bacterial GPL unsaturation elements and thus aim to decipher some of the biochemical pathways of unsaturation incorporation in bacterial GPLs. Finally, we discover aminoacyl-PGs not only in Gram-positive bacteria but also in Gram-negative , advancing our knowledge of the methods of surface charge modulation that Gram-negative organisms may adopt for antibiotic resistance.
甘油磷脂（GPLs）是细菌细胞膜的主要成分之一，具有高度复杂的结构，与生物物理膜性质如通透性和流动性直接相关。这种结构的复杂性源于单个 GPL 结构成分的巨大可变性，如酰基链长度和头基类型，并且通过双键和环丙烷环等修饰进一步放大。在这里，我们使用液相色谱法与高分辨率和高质量精度的紫外光解离质谱联用，对迄今为止细菌 GPL 修饰进行了最深入的研究。通过这样做，我们揭示了一系列多样化的、尚未被探索的 GPL 修饰，从酰基链羟基到新型头基结构。除了对这些修饰进行表征外，我们还阐明了细菌 GPL 不饱和元素的一般趋势，从而旨在破译细菌 GPL 中不饱和掺入的一些生化途径。最后，我们不仅在革兰氏阳性菌中发现了氨基酸酰基-PGs，也在革兰氏阴性菌中发现了它们，这提高了我们对革兰氏阴性菌可能采用的表面电荷调制方法的认识，以获得抗生素耐药性。
