Scheffers Dirk-Jan, Pinho Mariana G
Department of Molecular Microbiology, Institute of Molecular Cell Biology, Vrije Universiteit, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
Microbiol Mol Biol Rev. 2005 Dec;69(4):585-607. doi: 10.1128/MMBR.69.4.585-607.2005.
In order to maintain shape and withstand intracellular pressure, most bacteria are surrounded by a cell wall that consists mainly of the cross-linked polymer peptidoglycan (PG). The importance of PG for the maintenance of bacterial cell shape is underscored by the fact that, for various bacteria, several mutations affecting PG synthesis are associated with cell shape defects. In recent years, the application of fluorescence microscopy to the field of PG synthesis has led to an enormous increase in data on the relationship between cell wall synthesis and bacterial cell shape. First, a novel staining method enabled the visualization of PG precursor incorporation in live cells. Second, penicillin-binding proteins (PBPs), which mediate the final stages of PG synthesis, have been localized in various model organisms by means of immunofluorescence microscopy or green fluorescent protein fusions. In this review, we integrate the knowledge on the last stages of PG synthesis obtained in previous studies with the new data available on localization of PG synthesis and PBPs, in both rod-shaped and coccoid cells. We discuss a model in which, at least for a subset of PBPs, the presence of substrate is a major factor in determining PBP localization.
为了维持细胞形态并承受细胞内压力，大多数细菌被一层主要由交联聚合物肽聚糖（PG）组成的细胞壁所包围。对于各种细菌而言，影响PG合成的几种突变与细胞形态缺陷相关，这一事实凸显了PG对于维持细菌细胞形态的重要性。近年来，荧光显微镜在PG合成领域的应用极大地增加了关于细胞壁合成与细菌细胞形态之间关系的数据。首先，一种新的染色方法能够在活细胞中可视化PG前体的掺入。其次，介导PG合成最后阶段的青霉素结合蛋白（PBPs）已通过免疫荧光显微镜或绿色荧光蛋白融合技术在各种模式生物中定位。在这篇综述中，我们将先前研究中获得的关于PG合成最后阶段的知识与杆状细胞和球状细胞中PG合成及PBPs定位的新数据整合在一起。我们讨论了一种模型，其中至少对于一部分PBPs来说，底物的存在是决定PBP定位的主要因素。
