Affiliation:
1. Department of Molecular Genetics, University of Chicago, Illinois 60637.
Abstract
Accumulation of K+ ions and glutamate plays a primary role in maintaining osmotic balance in Escherichia coli, as illustrated by the high concentrations of these ions present in cells growing in medium of high osmolality. We found that two gamma-glutamyl peptides and glutamine also accumulated during growth at high osmolarity. In a mutant unable to make trehalose growing in 1.3 osM medium, glutathione, gamma-glutamylglutamine, and glutamine accumulated to levels of 73, 33, and 140 mumol/g of protein, respectively. In such cells, K+ was present at 1,450 mumol/g of protein, indicating that glutathione and gamma-glutamylglutamine accounted for less than 10% of the low-molecular-weight anions accumulated with K+. However, glutathione is needed for wild-type osmotolerance in this species. A mutant deficient in glutathione because of an insertion in the gshA gene was unable to grow above 1.4 osM, grew more slowly at intermediate osmolarities, and took longer to adapt to growth following osmotic upshock. The involvement of glutathione in osmoregulation was independent of the effect of glutathione on K+ retention.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
72 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