Control of septum thickness by the curvature of sepf polymers

Michaela Wenzel, Ilkay N. Celik Gulsoy, Yongqiang Gao, Zihao Teng, Joost Willemse, Martijn Middelkamp, Mariska G.M. van Rosmalen, Per W.B. Larsen, Nicole N. van der Wel, Gijs J.L. Wuite, Wouter H. Roos, Leendert W. Hamoen*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

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Gram-positive bacteria divide by forming a thick cross wall. How the thickness of this septal wall is controlled is unknown. In this type of bacteria, the key cell division protein FtsZ is anchored to the cell membrane by two proteins, FtsA and/or SepF. We have isolated SepF homologs from different bacterial species and found that they all polymerize into large protein rings with diameters varying from 19 to 44 nm. Interestingly, these values correlated well with the thickness of their septa. To test whether ring diameter determines septal thickness, we tried to construct different SepF chimeras with the purpose to manipulate the diameter of the SepF protein ring. This was indeed possible and confirmed that the conserved core domain of SepF regulates ring diameter. Importantly, when SepF chimeras with different diameters were expressed in the bacterial host Bacillus subtilis, the thickness of its septa changed accordingly. These results strongly support a model in which septal thickness is controlled by curved molecular clamps formed by SepF polymers attached to the leading edge of nascent septa. This also implies that the intrinsic shape of a protein polymer can function as a mold to shape the cell wall.

Original languageEnglish
Article numbere2002635118
Pages (from-to)1-9
Number of pages9
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number2
Early online date21 Dec 2020
Publication statusPublished - 12 Jan 2021


  • Bacillus subtilis
  • Cell division
  • FtsZ
  • SepF


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