Biophysical Society Thematic Meeting | Stockholm 2022

Physical and Quantitative Approaches to Overcome Antibiotic Resistance

Poster Abstracts

15-POS Board 15 COORDINATED CELL ENVELOPE BIOGENESIS IN GRAM-NEGATIVE BACTERIA Gideon Mamou 1 ; Federico Corona 2,5 ; Ruth Cohen-Khait 1 ; Nicholas G Housden 1 ; Vivian Yeung 1 ; Manuel Pazos 2 ; Dawei Sun 3 ; Pooja Sridhar 4 ; Timothy J Knowles 4 ; Colin Kleanthous 1 ; Waldemar Vollmer 2 ; 1 University of Oxford, Oxford, United Kingdom 2 Newcastle University, Newcastle upon Tyne, United Kingdom 3 Genetech Inc, San Francisco, CA, USA The cell envelope of Gram-negative bacteria is a tripartite structure composed of the symmetric phospholipid inner membrane, an asymmetric outer membrane (OM) and an intervening peptidoglycan layer. Linkages between the OM and the peptidoglycan are crucial to the maintenance of cellular integrity and enable survival in challenging environments. The functionality of the outer membrane relies on a variety of outer membrane proteins (OMPs), which are inserted by the β -barrel assembly machine, BAM. Previous studies have shown that growing Escherichia coli cells segregate old OMPs towards the cell poles by a process known as binary partitioning, the basis of which is unknown. Here, we demonstrate that peptidoglycan underpins the spatiotemporal organization of OMPs. Mature, tetrapeptide-rich peptidoglycan binds to BAM components and suppresses OMP foldase activity. Nascent peptidoglycan, which is enriched in pentapeptides and concentrated at septa, associates with BAM poorly and has little impact on its activity, leading to preferential insertion of OMPs at division sites. Consequently, OMP biogenesis is synchronized with cell wall growth and results in binary partitioning of OMPs as cells divide. Our study reveals that Gram-negative bacteria coordinate the assembly of two major cell envelope layers by rendering OMP biogenesis responsive to peptidoglycan maturation, a potential Achilles heel that could be exploited in future antibiotic design. 4 University of Birmingham, Birmingham, United Kingdom 5 European Molecular Biology Laboratory, Heidelberg, Germany

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