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The essential peptidoglycan glycosyltransferase MurG forms a complex with proteins involved in lateral envelope growth as well as with proteins involved in cell division in Escherichia coli

Authors

  • Tamimount Mohammadi,

    1. Molecular Cytology, Swammerdam Institute for Life Sciences, University of Amsterdam, Kruislaan 316, 1098 SM Amsterdam, PO Box 194062, 1090 GB Amsterdam, the Netherlands.
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  • Aneta Karczmarek,

    1. Molecular Cytology, Swammerdam Institute for Life Sciences, University of Amsterdam, Kruislaan 316, 1098 SM Amsterdam, PO Box 194062, 1090 GB Amsterdam, the Netherlands.
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  • Muriel Crouvoisier,

    1. Laboratoire des Enveloppes Bactériennes et Antibiotiques, CNRS, IBBMC UMR8619, Université Paris-Sud, Bât. 430, 91405 Orsay, France.
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  • Ahmed Bouhss,

    1. Laboratoire des Enveloppes Bactériennes et Antibiotiques, CNRS, IBBMC UMR8619, Université Paris-Sud, Bât. 430, 91405 Orsay, France.
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  • Dominique Mengin-Lecreulx,

    1. Laboratoire des Enveloppes Bactériennes et Antibiotiques, CNRS, IBBMC UMR8619, Université Paris-Sud, Bât. 430, 91405 Orsay, France.
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  • Tanneke Den Blaauwen

    Corresponding author
    1. Molecular Cytology, Swammerdam Institute for Life Sciences, University of Amsterdam, Kruislaan 316, 1098 SM Amsterdam, PO Box 194062, 1090 GB Amsterdam, the Netherlands.
      *E-mail blaauwen@science.uva.nl; Tel. (+31) 205255196; Fax (+31) 205257934.
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  • Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation.

*E-mail blaauwen@science.uva.nl; Tel. (+31) 205255196; Fax (+31) 205257934.

Summary

In Escherichia coli many enzymes including MurG are directly involved in the synthesis and assembly of peptidoglycan. MurG is an essential glycosyltransferase catalysing the last intracellular step of peptidoglycan synthesis. To elucidate its role during elongation and division events, localization of MurG using immunofluorescence microscopy was performed. MurG exhibited a random distribution in the cell envelope with a relatively higher intensity at the division site. This mid-cell localization was dependent on the presence of a mature divisome. Its localization in the lateral cell wall appeared to require the presence of MreCD. This could be indicative of a potential interaction between MurG and other proteins. Investigating this by immunoprecipitation revealed the association of MurG with MreB and MraY in the same protein complex. In view of this, the loss of rod shape of ΔmreBCD strain could be ascribed to the loss of MurG membrane localization. Consequently, this could prevent the localized supply of the lipid II precursor to the peptidoglycan synthesizing machinery involved in cell elongation. It is postulated that the involvement of MurG in the peptidoglycan synthesis concurs with two complexes, one implicated in cell elongation and the other in division. A model representing the first complex is proposed.

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