| Autor: |
Cho H; Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115, USA., Wivagg CN; Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA., Kapoor M; Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA., Barry Z; Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA., Rohs PDA; Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115, USA., Suh H; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA., Marto JA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.; Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA., Garner EC; Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA., Bernhardt TG; Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115, USA. |
| Abstrakt: |
Multi-protein complexes organized by cytoskeletal proteins are essential for cell wall biogenesis in most bacteria. Current models of the wall assembly mechanism assume that class A penicillin-binding proteins (aPBPs), the targets of penicillin-like drugs, function as the primary cell wall polymerases within these machineries. Here, we use an in vivo cell wall polymerase assay in Escherichia coli combined with measurements of the localization dynamics of synthesis proteins to investigate this hypothesis. We find that aPBP activity is not necessary for glycan polymerization by the cell elongation machinery, as is commonly believed. Instead, our results indicate that cell wall synthesis is mediated by two distinct polymerase systems, shape, elongation, division, sporulation (SEDS)-family proteins working within the cytoskeletal machines and aPBP enzymes functioning outside these complexes. These findings thus necessitate a fundamental change in our conception of the cell wall assembly process in bacteria. |
