BonA from Acinetobacter baumannii forms a divisome-localized decamer that supports outer envelope function

Rhys Grinter, Faye C. Morris, Rhys A. Dunstan, Pok Man Leung, Ashleigh Kropp, Matthew Belousoff, Sachith D. Gunasinghe, Nichollas E. Scott, Simone Beckham, Anton Y. Peleg, Chris Greening, Jian Li, Eva Heinz, Trevor Lithgow

Research output: Contribution to journalArticleResearchpeer-review

2 Citations (Scopus)

Abstract

Acinetobacter baumannii is a high-risk pathogen due to the rapid global spread of multidrug-resistant lineages. Its phylogenetic divergence from other ESKAPE pathogens means that determinants of its antimicrobial resistance can be difficult to extrapolate from other widely studied bacteria. A recent study showed that A. baumannii upregulates production of an outer membrane lipoprotein, which we designate BonA, in response to challenge with polymyxins. Here, we show that BonA has limited sequence similarity and distinct structural features compared to lipoproteins from other bacterial species. Analyses through X-ray crystallography, small-angle X-ray scattering, electron microscopy, and multiangle light scattering demonstrate that BonA has a dual BON (Bacterial OsmY and Nodulation) domain architecture and forms a decamer via an unusual oligomerization mechanism. This analysis also indicates this decamer is transient, suggesting dynamic oligomerization plays a role in BonA function. Antisera recognizing BonA shows it is an outer membrane protein localized to the divisome. Loss of BonA modulates the density of the outer membrane, consistent with a change in its structure or link to the peptidoglycan, and prevents motility in a clinical strain (ATCC 17978). Consistent with these findings, the dimensions of the BonA decamer are sufficient to permeate the pepti-doglycan layer, with the potential to form a membrane-spanning complex during cell division.

Original languageEnglish
Article numbere01480-21
Number of pages18
JournalmBio
Volume12
Issue number4
DOIs
Publication statusPublished - Aug 2021

Keywords

  • Acinetobacter baumannii
  • Cell division
  • Cell envelope
  • Outer membrane proteins

Cite this