Peptidoglycan hydrolases contribute to the generation of helical cell shape in Campylobacter and Helicobacter bacteria, while cytoskeletal or periskeletal proteins determine the curved, vibrioid cell shape of Caulobacter and Vibrio. Here, we identify a peptidoglycan hydrolase in the vibrioid-shaped predatory bacterium Bdellovibrio bacteriovorus which invades and replicates within the periplasm of Gram-negative prey bacteria. The protein, Bd1075, generates cell curvature in B. bacteriovorus by exerting LD-carboxypeptidase activity upon the predator cell wall as it grows inside spherical prey. Bd1075 localizes to the outer convex face of B. bacteriovorus; this asymmetric localization requires a nuclear transport factor 2-like (NTF2) domain at the protein C-terminus. We solve the crystal structure of Bd1075, which is monomeric with key differences to other LD-carboxypeptidases. Rod-shaped Δbd1075 mutants invade prey more slowly than curved wild-type predators and stretch invaded prey from within. We therefore propose that the vibrioid shape of B. bacteriovorus contributes to predatory fitness.
Bibliographical noteFunding Information:
This work was funded by a Wellcome Trust PhD studentship (215025/Z/18/Z) to E.J.B., a Becas Chile studentship (72180329) to M.V-D., a BBSRC studentship to A.W., and the UKRI Strategic Priorities Fund (https://www.ukri.org) EP/T002778/1 to W.V. R.E.S., C.L., and A.L.L. are currently funded by a Wellcome Trust Investigator Award in Science (209437/Z/17/Z). We thank Chloe Hudson for trials of Bd1075 purification, Daniela Vollmer for purification of PG, Joe Gray for mass spectrometry analysis of muropeptides, Rob Till for general laboratory support, and Block Allocation Group mx19880 for access to Diamond Synchrotron. Genome sequencing was provided by MicrobesNG (http://www.microbesng.uk), which is supported by the BBSRC (grant number BB/L024209/1). Electron microscopy was carried out at the Nanoscale and Microscale Research Centre at the University of Nottingham.
© 2022, The Author(s).
- Bdellovibrio bacteriovorus/genetics
- Cell Wall/metabolism
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Biochemistry, Genetics and Molecular Biology(all)