Outer membrane lipoprotein NlpI scaffolds peptidoglycan hydrolases within multi‐enzyme complexes in Escherichia coli

• Published in: The EMBO journal Vol. 39; no. 5; pp. e102246 - n/a
• Main Authors: Banzhaf, Manuel, Yau, Hamish CL, Verheul, Jolanda, Lodge, Adam, Kritikos, George, Mateus, André, Cordier, Baptiste, Hov, Ann Kristin, Stein, Frank, Wartel, Morgane, Pazos, Manuel, Solovyova, Alexandra S, Breukink, Eefjan, van Teeffelen, Sven, Savitski, Mikhail M, den Blaauwen, Tanneke, Typas, Athanasios, Vollmer, Waldemar
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 02.03.2020; Springer Nature B.V; EMBO Press; John Wiley and Sons Inc
• Subjects: Adapters; Antibiotics; Bacteria; bacterial cell envelope; Biochemistry; Biochemistry, Molecular Biology; Biodegradation; Biosynthesis; Cell division; Cell size; Cell Wall - enzymology; Cell walls; E coli; Elongation; EMBO23; endopeptidase; Endopeptidases - genetics; Endopeptidases - metabolism; Enlargement; Enzymatic activity; Enzymes; Escherichia coli; Escherichia coli - enzymology; Escherichia coli - genetics; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Hydrolase; Life Sciences; Lipoproteins; Lipoproteins - genetics; Lipoproteins - metabolism; Localization; Mechanical properties; Membranes; Multienzyme Complexes; N-Acetylmuramoyl-L-alanine Amidase - genetics; N-Acetylmuramoyl-L-alanine Amidase - metabolism; Osmotic stress; outer membrane lipoprotein; Penicillin; penicillin‐binding protein; peptidoglycan; Peptidoglycan - metabolism; Peptidoglycans; Regulators; Saccule; peptidoglycan; bacterial cell envelope; endopeptidase; outer membrane lipoprotein; penicillin‐binding protein; penicillin-binding protein; Virology & Host Pathogen Interaction; outer membrane lipopro- tein; peptidoglycan Subject Category Microbiology
• ISSN: 0261-4189; 1460-2075; 1460-2075
• DOI: 10.15252/embj.2019102246

The peptidoglycan (PG) sacculus provides bacteria with the mechanical strength to maintain cell shape and resist osmotic stress. Enlargement of the mesh‐like sacculus requires the combined activity of peptidoglycan synthases and hydrolases. In Escherichia coli , the activity of two PG synthases is driven by lipoproteins anchored in the outer membrane (OM). However, the regulation of PG hydrolases is less well understood, with only regulators for PG amidases having been described. Here, we identify the OM lipoprotein NlpI as a general adaptor protein for PG hydrolases. NlpI binds to different classes of hydrolases and can specifically form complexes with various PG endopeptidases. In addition, NlpI seems to contribute both to PG elongation and division biosynthetic complexes based on its localization and genetic interactions. Consistent with such a role, we reconstitute PG multi‐enzyme complexes containing NlpI, the PG synthesis regulator LpoA, its cognate bifunctional synthase, PBP1A, and different endopeptidases. Our results indicate that peptidoglycan regulators and adaptors are part of PG biosynthetic multi‐enzyme complexes, regulating and potentially coordinating the spatiotemporal action of PG synthases and hydrolases. Synopsis In bacteria, enzyme activities regulating peptidoglycan biosynthesis and degradation have to be adjusted during cell wall growth. Here, the outer membrane‐anchored lipoprotein NlpI is shown to facilitate formation of peptidoglycan synthase and hydrolase multi‐enzyme complexes to coordinate correct enlargement of the cell wall peptidoglycan layer in E. coli . NlpI binds to different classes of peptidoglycan hydrolases. NlpI can specifically form multimeric complexes with various endopeptidases. NlpI contributes to peptidoglycan biosynthetic complexes active in cell elongation and cell division based on its cellular localization and genetic interactions. NlpI forms multi‐enzyme complexes containing peptidoglycan synthases and hydrolases in vitro . Graphical Abstract An adaptor protein for peptidoglycan hydrolases and synthases coordinates bacterial cell wall growth.