Abstract
ABSTRACTAlthough the peptidoglycan cell wall is an essential structural and morphological feature of most bacterial cells, the extracytoplasmic enzymes involved in its synthesis are frequently dispensable under standard culture conditions. By modulating a single growth parameter—extracellular pH—we discovered a subset of these so-called “redundant” enzymes in Escherichia coli are required for maximal fitness across pH environments. Among these pH specialists are the class A penicillin binding proteins PBP1 a and PBP1 b; defects in these enzymes attenuate growth in alkaline and acidic conditions, respectively. Genetic, biochemical, and cytological studies demonstrate that synthase activity is required for cell wall integrity across a wide pH range, and differential activity across pH environments significantly alters intrinsic resistance to cell wall active antibiotics. Together, our findings reveal previously thought to be redundant enzymes are instead specialized for distinct environmental niches, thereby ensuring robust growth and cell wall integrity in a wide range of conditions.
Publisher
Cold Spring Harbor Laboratory
Reference70 articles.
1. Ingraham JL. Effect of temperature, pressure, Ph, and osmotic stress on growth. Escherichia coli and Salmonella typhimurium: cellular and molecular biology. American Society for Microbilolgy; 1992;:1570–8.
2. Structural and functional properties of porin channels in E. coli outer membranes;Experientia.,1990
3. pH homeostasis in Escherichia coli: measurement by 31P nuclear magnetic resonance of methylphosphonate and phosphate.
4. pH of the Cytoplasm and Periplasm of
Escherichia coli
: Rapid Measurement by Green Fluorescent Protein Fluorimetry
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献