Tol Energy-Driven Localization of Pal and Anchoring to the Peptidoglycan Promote Outer-Membrane Constriction

J Mol Biol. 2019 Aug 9;431(17):3275-3288. doi: 10.1016/j.jmb.2019.05.039. Epub 2019 May 31.


During cell division, gram-negative bacteria must coordinate inner-membrane invagination, peptidoglycan synthesis and cleavage and outer-membrane (OM) constriction. The OM constriction remains largely enigmatic, and the nature of this process, passive or active, is under debate. The proton-motive force-dependent Tol-Pal system performs a network of interactions within these three compartments. Here we confirm that the trans-envelope Tol-Pal complex accumulates at constriction site in Escherichia coli. We show that the inner-membrane complex composed of TolA, TolQ and TolR recruits the OM complex TolB-Pal to the septum, in an energy-dependent process. Pal recruitment then allows its binding to peptidoglycan and subsequently OM constriction. Our results provide evidence that the constriction of the OM is an energized process.

Keywords: OM invagination; Tol–Pal system; membrane vesicles; molecular motor; septum.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Outer Membrane Proteins / chemistry*
  • Bacterial Outer Membrane Proteins / metabolism
  • Cell Division
  • Cloning, Molecular
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism
  • Lipoproteins / chemistry*
  • Membrane Proteins
  • Multigene Family
  • Peptidoglycan / chemistry*


  • Bacterial Outer Membrane Proteins
  • Escherichia coli Proteins
  • ExcC protein, E coli
  • Lipoproteins
  • Membrane Proteins
  • Peptidoglycan
  • tolA protein, E coli
  • tolQ protein, E coli
  • tolR protein, E coli