Inactivation of the monofunctional peptidoglycan glycosyltransferase SgtB allows Staphylococcus aureus to survive in the absence of lipoteichoic acid
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Author(s)
Karinou, Eleni
Schuster, Christopher
Pazos, Manuel
Vollmer, Waldemar
Grundling, Angelika
Type
Journal Article
Abstract
The cell wall of Staphylococcus aureus is composed of peptidoglycan and the anionic polymers lipoteichoic acid (LTA) and wall teichoic acid. LTA is required for growth and normal cell morphology in S. aureus. Strains lacking LTA are usually viable only when grown under osmotically stabilizing conditions or after the acquisition of compensatory mutations. LTA-negative suppressor strains with inactivating mutations in gdpP, which resulted in increased intracellular c-di-AMP levels, were described previously. Here, we sought to identify factors other than c-di-AMP that allow S. aureus to survive without LTA. LTA-negative strains able to grow in unsupplemented medium were obtained and found to contain mutations in sgtB, mazE, clpX, or vraT. The growth improvement through mutations in mazE and sgtB was confirmed by complementation analysis. We also showed that an S. aureus sgtB transposon mutant, with the monofunctional peptidoglycan glycosyltransferase SgtB inactivated, displayed a 4-fold increase in the MIC of oxacillin, suggesting that alterations in the peptidoglycan structure could help bacteria compensate for the lack of LTA. Muropeptide analysis of peptidoglycans isolated from a wild-type strain and sgtB mutant strain did not reveal any sizable alterations in the peptidoglycan structure. In contrast, the peptidoglycan isolated from an LTA-negative ltaS mutant strain showed a significant reduction in the fraction of highly cross-linked peptidoglycan, which was partially rescued in the sgtB ltaS double mutant suppressor strain. Taken together, these data point toward an important function of LTA in cell wall integrity through its necessity for proper peptidoglycan assembly.
Date Issued
2018-12-07
Date Acceptance
2018-10-08
Citation
Journal of Bacteriology, 2018, 201 (1)
ISSN
0021-9193
Publisher
American Society for Microbiology
Journal / Book Title
Journal of Bacteriology
Volume
201
Issue
1
Copyright Statement
© 2018 Karinou et al.
This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/).
This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/).
License URL
Sponsor
Commission of the European Communities
Wellcome Trust
Grant Number
260371
100289/Z/12/Z
Subjects
Science & Technology
Life Sciences & Biomedicine
Microbiology
Staphylococcus aureus
cell wall
lipoteichoic acid
C-DI-AMP
BETA-LACTAM RESISTANCE
WALL TEICHOIC-ACIDS
CELL-WALL
SIGMA-FACTOR
BINDING
IDENTIFICATION
SYNTHASE
GENES
PROTEINS
06 Biological Sciences
11 Medical And Health Sciences
07 Agricultural And Veterinary Sciences
Publication Status
Published
Article Number
e00574-18