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Dead‐end intermediates in the enterobacterial common antigen pathway induce morphological defects in Escherichia coli by competing for undecaprenyl phosphate
Author(s) -
Jorgenson Matthew A.,
Kannan Suresh,
Laubacher Mary E.,
Young Kevin D.
Publication year - 2016
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/mmi.13284
Subject(s) - biology , peptidoglycan , lipid ii , bacterial outer membrane , escherichia coli , biosynthesis , periplasmic space , biochemistry , mutant , cell wall , microbiology and biotechnology , glycolipid , cell membrane , cell , enzyme , gene
Summary Bacterial morphology is determined primarily by the architecture of the peptidoglycan ( PG ) cell wall, a mesh‐like layer that encases the cell. To identify novel mechanisms that create or maintain cell shape in E scherichia coli , we used flow cytometry to screen a transposon insertion library and identified a wec E mutant that altered cell shape, causing cells to filament and swell. WecE is a sugar aminotransferase involved in the biosynthesis of enterobacterial common antigen ( ECA ), a non‐essential outer membrane glycolipid of the E nterobacteriaceae . Loss of wec E interrupts biosynthesis of ECA and causes the accumulation of the undecaprenyl pyrophosphate‐linked intermediate ECA ‐lipid II . The wec E shape defects were reversed by: (i) preventing initiation of ECA biosynthesis, (ii) increasing the synthesis of the lipid carrier undecaprenyl phosphate ( U nd‐ P ), (iii) diverting U nd‐ P to PG synthesis or (iv) promoting U nd‐ P recycling. The results argue that the buildup of ECA ‐lipid II sequesters part of the pool of U nd‐ P , which, in turn, adversely affects PG synthesis. The data strongly suggest there is competition for a common pool of U nd‐ P , whose proper distribution to alternate metabolic pathways is required to maintain normal cell shape in E . coli .