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Analysis of membrane protein interaction: ToxR can dimerize the amino terminus of phage lambda repressor
Author(s) -
Dziejman Michelle,
Mekalanos John J.
Publication year - 1994
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1994.tb00443.x
Subject(s) - biology , periplasmic space , repressor , vibrio cholerae , operon , cholera toxin , bacteriophage , lambda phage , microbiology and biotechnology , two hybrid screening , integral membrane protein , escherichia coli , genetics , membrane protein , gene , membrane , bacteria , transcription factor
Summary The ToxR protein of Vibrio cholerae is an integral membrane protein that co‐ordinately regulates virulence determinant expression. ToxR directiy 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 λ‐ToxR chimeric proteins using the DNA‐binding domain of the phage λ 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.