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Transmembrane transport of peptidoglycan precursors across model and bacterial membranes
Author(s) -
Van Dam Vincent,
Sijbrandi Robert,
Kol Matthijs,
Swiezewska Ewa,
De Kruijff Ben,
Breukink Eefjan
Publication year - 2007
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2007.05722.x
Subject(s) - periplasmic space , transmembrane protein , biology , lipid ii , vesicle , peptidoglycan , cytoplasm , biochemistry , membrane , lipid bilayer , cell membrane , membrane transport , biophysics , chromosomal translocation , bacterial outer membrane , biological membrane , microbiology and biotechnology , escherichia coli , cell wall , gene , receptor
Summary Translocation of the peptidoglycan precursor Lipid II across the cytoplasmic membrane is a key step in bacterial cell wall synthesis, but hardly understood. Using NBD‐labelled Lipid II, we showed by fluorescence and TLC assays that Lipid II transport does not occur spontaneously and is not induced by the presence of single spanning helical transmembrane peptides that facilitate transbilayer movement of membrane phospholipids. MurG catalysed synthesis of Lipid II from Lipid I in lipid vesicles also did not result in membrane translocation of Lipid II. These findings demonstrate that a specialized protein machinery is needed for transmembrane movement of Lipid II. In line with this, we could demonstrate Lipid II translocation in isolated Escherichia coli inner membrane vesicles and this transport could be uncoupled from the synthesis of Lipid II at low temperatures. The transport process appeared to be independent from an energy source (ATP or proton motive force). Additionally, our studies indicate that translocation of Lipid II is coupled to transglycosylation activity on the periplasmic side of the inner membrane.