Lytic transglycosylases mitigate periplasmic crowding by degrading soluble cell wall turnover products

eLife

Michael S van Nieuwenhze¹  Laura Alvarez²  Felipe Cava²  Kelly M Rosch³  Garrett Sean Wang³  Asraa Ahmed⁴  Anna Isabell Weaver⁵  Tobias Dörr⁶ 

[1] Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Sweden;Department of Chemistry, Indiana University, Bloomington, United States;The Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå University, Umeå, Sweden;Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, United States;Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, United States;Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, United States;Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, United States;Department of Microbiology, Cornell University, Ithaca, United States;Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, United States;Department of Microbiology, Cornell University, Ithaca, United States;Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, United States;

关键词: peptidoglycan;    lytic transglycosylase;    Vibrio cholerae;    periplasm;    Other;   

DOI  :  10.7554/eLife.73178

来源: eLife Sciences Publications, Ltd

【 摘 要 】

The peptidoglycan cell wall is a predominant structure of bacteria, determining cell shape and supporting survival in diverse conditions. Peptidoglycan is dynamic and requires regulated synthesis of new material, remodeling, and turnover – or autolysis – of old material. Despite exploitation of peptidoglycan synthesis as an antibiotic target, we lack a fundamental understanding of how peptidoglycan synthesis and autolysis intersect to maintain the cell wall. Here, we uncover a critical physiological role for a widely misunderstood class of autolytic enzymes, lytic transglycosylases (LTGs). We demonstrate that LTG activity is essential to survival by contributing to periplasmic processes upstream and independent of peptidoglycan recycling. Defects accumulate in Vibrio cholerae LTG mutants due to generally inadequate LTG activity, rather than absence of specific enzymes, and essential LTG activities are likely independent of protein-protein interactions, as heterologous expression of a non-native LTG rescues growth of a conditional LTG-null mutant. Lastly, we demonstrate that soluble, uncrosslinked, endopeptidase-dependent peptidoglycan chains, also detected in the wild-type, are enriched in LTG mutants, and that LTG mutants are hypersusceptible to the production of diverse periplasmic polymers. Collectively, our results suggest that LTGs prevent toxic crowding of the periplasm with synthesis-derived peptidoglycan polymers and, contrary to prevailing models, that this autolytic function can be temporally separate from peptidoglycan synthesis.

【 授权许可】

CC BY