Regulation of envelope protein composition during adaptation to osmotic stress in Escherichia coli

Barron, A., May, G. , Bremer, E. and Villarejo, M. (1986) Regulation of envelope protein composition during adaptation to osmotic stress in Escherichia coli. Journal of Bacteriology, 167(2), pp. 433-438. (doi:10.1128/jb.167.2.433-438.1986) (PMID:3015869) (PMCID:PMC212906)

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Abstract

Adaptation to osmotic stress alters the amounts of several specific proteins in the Escherichia coli K-12 envelope. The most striking feature of the response to elevated osmolarity was the strong induction of a periplasmic protein with an Mr of 31,000. This protein was absent in mutants with lambda plac Mu insertions in an osmotically inducible locus mapping near 58 min. The insertions are likely to be in proU, a locus encoding a transport activity for the osmoprotectants glycine betaine and proline. Factors affecting the extent of proU induction were identified by direct examination of periplasmic proteins on sodium dodecyl sulfate gels and by measuring beta-galactosidase activity from proU-lac fusions. Expression was stimulated by increasing additions of salt or sucrose to minimal medium, up to a maximum at 0.5 M NaCl. Exogenous glycine betaine acted as an osmoregulatory signal; its addition to the high-osmolarity medium substantially repressed the expression of the 31,000-dalton periplasmic protein and the proU-lac+ fusions. Elevated osmolarity also caused the appearance of a second periplasmic protein (Mr = 16,000), and severe reduction in the amounts of two others. In the outer membrane, the well-characterized repression of OmpF by high osmolarity was observed and was reversed by glycine betaine. Additional changes in membrane composition were also responsive to glycine betaine regulation.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:May, Dr Gerhard
Authors: Barron, A., May, G., Bremer, E., and Villarejo, M.
Subjects:Q Science > QH Natural history > QH345 Biochemistry
Q Science > QH Natural history > QH426 Genetics
Q Science > QR Microbiology
College/School:College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
Journal Name:Journal of Bacteriology
Publisher:American Society for Microbiology
ISSN:0021-9193
ISSN (Online):1098-5530

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