Relative binding affinities of OmpR and OmpR-phosphate at the ompF and ompC regulatory sites - PubMed (original) (raw)
. 1998 Sep 4;281(5):857-70.
doi: 10.1006/jmbi.1998.1985.
Affiliations
- PMID: 9719640
- DOI: 10.1006/jmbi.1998.1985
Relative binding affinities of OmpR and OmpR-phosphate at the ompF and ompC regulatory sites
C G Head et al. J Mol Biol. 1998.
Abstract
In Escherichia coli, porin gene expression is regulated, in part, by the two-component regulatory system consisting of the two proteins EnvZ and OmpR. EnvZ is an integral inner membrane protein that is phosphorylated by cytoplasmic ATP on a histidine residue. EnvZ modulates the activity of OmpR by phosphorylation and dephosphorylation. Phospho-OmpR (OmpR-P) binds to the porin genes ompF and ompC to regulate their expression. The simple affinity model predicts that as the concentration of OmpR-P increases, initially high-affinity binding sites on ompF are filled. Then binding sites of lower affinity on ompF and ompC are occupied and this ordered binding accounts for the differential expression of the porin genes. We demonstrate that acetyl phosphate phosphorylates OmpR at aspartate 55, the same residue phosphorylated by the kinase EnvZ. Quantification of the level of OmpR-P by HPLC and direct measurement of the binding affinities enabled us to test the affinity model. Our results indicate that phosphorylation dramatically increases the affinity of OmpR for its binding sites (greater than tenfold). We also show that the affinities of OmpR-P for F1 and C1 binding sites are not sufficiently different to provide a strong basis for discrimination. The consequences of these observations for the simple affinity model are considered.
Copyright 1998 Academic Press
Similar articles
- Robustness and the cycle of phosphorylation and dephosphorylation in a two-component regulatory system.
Batchelor E, Goulian M. Batchelor E, et al. Proc Natl Acad Sci U S A. 2003 Jan 21;100(2):691-6. doi: 10.1073/pnas.0234782100. Epub 2003 Jan 9. Proc Natl Acad Sci U S A. 2003. PMID: 12522261 Free PMC article. - A phosphorylation site mutant of OmpR reveals different binding conformations at ompF and ompC.
Mattison K, Oropeza R, Byers N, Kenney LJ. Mattison K, et al. J Mol Biol. 2002 Jan 25;315(4):497-511. doi: 10.1006/jmbi.2001.5222. J Mol Biol. 2002. PMID: 11812125 - A single amino acid substitution in the C terminus of OmpR alters DNA recognition and phosphorylation.
Tran VK, Oropeza R, Kenney LJ. Tran VK, et al. J Mol Biol. 2000 Jun 23;299(5):1257-70. doi: 10.1006/jmbi.2000.3809. J Mol Biol. 2000. PMID: 10873450 - Signal transduction in bacteria: kinases that control gene expression.
Igo MM, Slauch JM, Silhavy TJ. Igo MM, et al. New Biol. 1990 Jan;2(1):5-9. New Biol. 1990. PMID: 1964084 Review.
Cited by
- To ∼P or Not to ∼P? Non-canonical activation by two-component response regulators.
Desai SK, Kenney LJ. Desai SK, et al. Mol Microbiol. 2017 Jan;103(2):203-213. doi: 10.1111/mmi.13532. Epub 2016 Oct 11. Mol Microbiol. 2017. PMID: 27656860 Free PMC article. Review. - A fundamental regulatory mechanism operating through OmpR and DNA topology controls expression of Salmonella pathogenicity islands SPI-1 and SPI-2.
Cameron AD, Dorman CJ. Cameron AD, et al. PLoS Genet. 2012;8(3):e1002615. doi: 10.1371/journal.pgen.1002615. Epub 2012 Mar 22. PLoS Genet. 2012. PMID: 22457642 Free PMC article. - The acetate switch.
Wolfe AJ. Wolfe AJ. Microbiol Mol Biol Rev. 2005 Mar;69(1):12-50. doi: 10.1128/MMBR.69.1.12-50.2005. Microbiol Mol Biol Rev. 2005. PMID: 15755952 Free PMC article. Review. - A simulation model of Escherichia coli osmoregulatory switch using E-CELL system.
Srividhya KV, Krishnaswamy S. Srividhya KV, et al. BMC Microbiol. 2004 Nov 30;4:44. doi: 10.1186/1471-2180-4-44. BMC Microbiol. 2004. PMID: 15571621 Free PMC article.
Publication types
MeSH terms
Substances
LinkOut - more resources
Full Text Sources
Molecular Biology Databases