In situ visualization of Braun's lipoprotein on E. coli sacculi.
Qi ShengMeng-Yao ZhangSi-Min LiuZhuo-Wei ChenPei-Ling YangHong-Su ZhangMeng-Yun LiuKang LiLong-Sheng ZhaoNing-Hua LiuLu-Ning LiuXiu-Lan ChenJamie K HobbsSimon J FosterYu-Zhong ZhangHai-Nan SuPublished in: Science advances (2023)
Braun's lipoprotein (Lpp) plays a major role in stabilizing the integrity of the cell envelope in Escherichia coli , as it provides a covalent cross-link between the outer membrane and the peptidoglycan layer. An important challenge in elucidating the physiological role of Lpp lies in attaining a detailed understanding of its distribution on the peptidoglycan layer. Here, using atomic force microscopy, we visualized Lpp directly on peptidoglycan sacculi. Lpp is homogeneously distributed over the outer surface of the sacculus at a high density. However, it is absent at the constriction site during cell division, revealing its role in the cell division process with Pal, another cell envelope-associated protein. Collectively, we have established a framework to elucidate the distribution of Lpp and other peptidoglycan-bound proteins via a direct imaging modality.