Biomaterial Database

Suppression of a mutation in OmpR at the putative phosphorylation center by a mutant EnvZ protein in Escherichia coli. 1991

R E Brissette, and K L Tsung, and M Inouye

Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Rutgers, Piscataway 08854.

Phosphorylation of OmpR, a transcription activator for ompF and ompC expression, is essential for its function and has been shown to be mediated in vitro by EnvZ, a transmembrane sensory receptor protein. On the basis of the three-dimensional structure of CheY which has an extensive sequence similarity with OmpR, three aspartic residues, D11, D12, and D55, of OmpR are considered to form a triacidic pocket serving as the phosphorylation center. When these aspartic acid residues were replaced with asparagine (D11N) or glutamine (D12Q and D55Q), ompF and ompC expression was almost completely blocked. Two pseudorevertants of the D11N mutation were isolated: one of them is a mutation in EnvZ (G240E), and the other is a mutation in OmpR (S48F). The envZ mutation (G240E) by itself was found to confer a phenotype very similar to that of the well known envZ11 mutation (T247R), suggesting that EnvZ (G240E) is an elevated kinase for OmpR. Consistent with this notion, EnvZ (T247R) was also able to suppress the D11N mutation in OmpR. An in vitro phosphorylation study showed that while the wild-type OmpR was phosphorylated by EnvZ, the D11N OmpR was not. These results suggest that the D11N mutation alters OmpR conformation in such a way that OmpR is very poorly phosphorylated by EnvZ. On the basis of the in vivo and in vitro analysis, the mechanisms by which the G240E mutation in EnvZ and the S48F mutation in OmpR suppress the D11N mutation in OmpR are discussed.

UI	MeSH Term	Description	Entries
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D009097	Multienzyme Complexes	Systems of enzymes which function sequentially by catalyzing consecutive reactions linked by common metabolic intermediates. They may involve simply a transfer of water molecules or hydrogen atoms and may be associated with large supramolecular structures such as MITOCHONDRIA or RIBOSOMES.	Complexes, Multienzyme
D010766	Phosphorylation	The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.	Phosphorylations
D010957	Plasmids	Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.	Episomes,Episome,Plasmid
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D006898	Hydroxylamines	Organic compounds that contain the (-NH2OH) radical.
D001425	Bacterial Outer Membrane Proteins	Proteins isolated from the outer membrane of Gram-negative bacteria.	OMP Proteins,Outer Membrane Proteins, Bacterial,Outer Membrane Lipoproteins, Bacterial
D013489	Suppression, Genetic	Mutation process that restores the wild-type PHENOTYPE in an organism possessing a mutationally altered GENOTYPE. The second "suppressor" mutation may be on a different gene, on the same gene but located at a distance from the site of the primary mutation, or in extrachromosomal genes (EXTRACHROMOSOMAL INHERITANCE).	Suppressor Mutation,Genetic Suppression,Genetic Suppressions,Mutation, Suppressor,Mutations, Suppressor,Suppressions, Genetic,Suppressor Mutations
D014158	Transcription, Genetic	The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.	Genetic Transcription