title: Analysis of membrane protein interaction: ToxR can dimerize the amino terminus of phage lambda repressor.
abstract: The ToxR protein of Vibrio cholerae is an integral membrane protein that co-ordinately regulates virulence determinant expression. ToxR directly activates the cholera toxin operon, but maximal activation is achieved in the presence of ToxS, an integral membrane protein thought to interact with ToxR periplasmic sequences. Studies that substitute alkaline phosphatase sequences for the periplasmic domain of ToxR have led to a model for ToxR activation based on dimerization and ToxS interaction. We constructed lambda-ToxR chimeric proteins using the DNA-binding domain of the phage lambda repressor, which cannot effectively dimerize by itself, to assess the ability of ToxR to form dimers in Escherichia coli. The results suggest that ToxR sequences can propagate dimerization, and that ToxS can influence the ability to dimerize.
authors.affiliation: Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115.
authors.forename: M
authors.initials: M
authors.lastname: Dziejman
authors.forename: J J
authors.initials: JJ
authors.lastname: Mekalanos
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli; D016350:Leucine Zippers; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism*; D012097:Repressor Proteins / Q000737:chemistry / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*; D014734:Vibrio cholerae / Q000235:genetics / Q000378:metabolism*; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C016649:phage repressor proteins; C499324:toxR protein, Vibrio cholerae; C066719:toxR protein, bacteria; D000469:Alkaline Phosphatase