GcvR interacts with GcvA to inhibit activation of the Escherichia coli glycine cleavage operon

• Published in: Microbiology (Society for General Microbiology) 2001-08, Vol.147 (8), p.2215-2221
• Main Authors: Ghrist, Angela C, Heil, Gary, Stauffer, George V
• Format: Article
• Language: English
• Subjects: Amino Acid Oxidoreductases - genetics; Amino Acid Oxidoreductases - metabolism; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biological and medical sciences; Carrier Proteins - genetics; Carrier Proteins - metabolism; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Escherichia coli; Escherichia coli - enzymology; Escherichia coli - genetics; Escherichia coli - growth & development; Escherichia coli Proteins; Fundamental and applied biological sciences. Psychology; GcvA protein; gcvH gene; gcvP gene; GcvR protein; gcvT gene; gcvTHP gene; Gene Expression Regulation, Bacterial; Genetics; glycine; Microbiology; Multienzyme Complexes - genetics; Multienzyme Complexes - metabolism; Mutation; Operon; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Repressor Proteins - genetics; Repressor Proteins - metabolism; Transcription Factors - genetics; Transcription Factors - metabolism; Transferases - genetics; Transferases - metabolism
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/00221287-147-8-2215

Department of Microbiology, The University of Iowa, Iowa City, IA 52242, USA 1 Author for correspondence: George V. Stauffer. Tel: [phone]. Fax: [phone]. e-mail: george-stauffer{at}uiowa.edu The Escherichia coli glycine cleavage enzyme system, encoded by the gcvTHP operon, catalyses the oxidative cleavage of glycine to CO 2 , NH 3 and a one-carbon methylene group. Transcription of the gcv operon is positively regulated by GcvA and negatively regulated by GcvA and GcvR. Using a LexA-based system for analysing protein heterodimerization, it is shown that GcvR interacts directly with GcvA in vivo to repress gcvTHP expression. Several mutations in either gcvA or gcvR that result in a loss of gcv repression also result in a loss of GcvA/GcvR heterodimerization. Finally, it is shown that the C-terminal half of GcvA is involved in its interaction with GcvR, whilst the entire GcvR protein appears to be necessary for heterodimerization. Keywords: gcvTHP , repressor, activator, repression, antiactivation Abbreviations: AP, ampicillin; DBD, DNA-binding domain; gcv , gcvTHP ; TC, tetracycline; TPEG, phenylethyl-ß- D -thiogalactoside