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The low‐molecular‐mass, penicillin‐binding proteins DacB and DacC combine to modify peptidoglycan cross‐linking and allow stable Type IV pilus expression in Neisseria gonorrhoeae
Author(s) -
Obergfell Kyle P.,
Schaub Ryan E.,
Priniski Lauren L.,
Dillard Joseph P.,
Seifert H Steven
Publication year - 2018
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.13955
Subject(s) - biology , neisseria gonorrhoeae , pilus , peptidoglycan , mutant , microbiology and biotechnology , cell envelope , virulence , penicillin binding proteins , phenotype , gene , penicillin , genetics , antibiotics , escherichia coli
Summary Neisseria gonorrhoeae is the causative agent of the sexually transmitted infection gonorrhea and is adapted to survive in humans, its only host. The N. gonorrhoeae cell wall is critical for maintaining envelope integrity, resisting immune cell killing and production of cytotoxic peptidoglycan (PG) fragments. Deletion of the N. gonorrhoeae strain FA1090 genes encoding two predicted low‐molecular‐mass, penicillin‐binding proteins (LMM PBPs), DacB and DacC, substantially altered the PG cross‐linking. Loss of the DacB peptidase resulted in global alterations to the PG composition, while loss of the DacC protein affected a much narrower subset of PG peptide components. A double Δ dacB/ Δ dacC mutant resembled the Δ dacB single mutant, but had an even greater level of cross‐linked PG. While single Δ dacB or Δ dacC mutants did not show any major phenotypes, the Δ dacB/ Δ dacC mutant displayed an altered cellular morphology, decreased resistance to antibiotics and increased sensitivity to detergent‐mediated death. Loss of the two proteins also drastically reduced the number of Type IV pili (Tfp), a critical virulence factor. The decreased piliation reduced transformation efficiency and correlated with increased growth rate. While these two LMM PBPs differentially alter the PG composition, their overlapping effects are essential to proper envelope function and expression of factors critical for pathogenesis.