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Full-Text Articles in Biochemistry
Role Of The Mar-Sox-Rob Regulon In Regulating Outer Membrane Porin Expression, Lon Chubiz, Christopher Rao
Role Of The Mar-Sox-Rob Regulon In Regulating Outer Membrane Porin Expression, Lon Chubiz, Christopher Rao
Biology Department Faculty Works
Multiple factors control the expression of the outer membrane porins OmpF and OmpC in Escherichia coli. In this work, we investigated the role of the mar-sox-rob regulon in regulating outer membrane porin expression in response to salicylate. We provide both genetic and physiological evidence that MarA and Rob can independently activate micF transcription in response to salicylate, leading to reduced OmpF expression. MarA was also found to repress OmpF expression through a MicF-independent pathway. In the case of OmpC, we found that its transcription was moderately increased in response to salicylate. However, this increase was independent of MarA and Rob. …
Aromatic Acid Metabolites Of Escherichia Coli K-12 Can Induce The Marrab Operon, Lon Chubiz, Christopher Rao
Aromatic Acid Metabolites Of Escherichia Coli K-12 Can Induce The Marrab Operon, Lon Chubiz, Christopher Rao
Biology Department Faculty Works
MarR is a key regulator of the marRAB operon involved in antibiotic resistance and solvent stress tolerance in Escherichia coli. We show that two metabolic intermediates, 2,3-dihydroxybenzoate and anthranilate, involved in enterobactin and tryptophan biosynthesis, respectively, can activate marRAB transcription. We also found that a third intermediate involved in ubiquinone biosynthesis, 4-hydroxybenzoate, activates marRAB transcription in the absence of TolC. Of the three, however, only 2,3-dihydroxybenzoate directly binds MarR and affects its activity.
The Rna-Binding Site Of Bacteriophage Qβ Coat Protein, Francis Lim, Marc Spingola, David Peabody
The Rna-Binding Site Of Bacteriophage Qβ Coat Protein, Francis Lim, Marc Spingola, David Peabody
Biology Department Faculty Works
The coat proteins of the RNA bacteriophages Qβ and MS2 are specific RNA binding proteins. Although they possess common tertiary structures, they bind different RNA stem loops and thus provide useful models of specific protein-RNA recognition. Although the RNA-binding site of MS2 coat protein has been extensively characterized previously, little is known about Qβ. Here we describe the isolation of mutants that define the RNA-binding site of Qβ coat protein, showing that, as with MS2, it resides on the surface of a large β-sheet. Mutations are also described that convert Qβ coat protein to the RNA binding specificity of MS2. …
Altering The Rna Binding Specificity Of A Translational Repressor, F Lim, Marc Spingola, D Peabody
Altering The Rna Binding Specificity Of A Translational Repressor, F Lim, Marc Spingola, D Peabody
Biology Department Faculty Works
The coat proteins of RNA phages MS2 and GA are specific RNA-binding proteins which function to encapsidate viral RNA and to translationally repress synthesis of the viral replicase. The two proteins have highly homologous amino acid sequences, yet they show different RNA binding specificities, recognizing RNA stem-loop structures which differ primarily in the nucleotide sequences of their loops. We sought to convert MS2 coat protein to the RNA binding specificity of GA through the introduction of GA-like amino acid substitutions into the MS2 coat protein RNA-binding site. The effects of the mutations were determined by measuring the affinity of the …