Open AccessTranslational Restarts: AUG Reinitiation of a lac Repressor Fragment
Author(s) -
Terry Platt,
Klaus Weber,
Don Ganem,
Jeffrey H Miller
Publication year - 1972
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.69.4.897
Subject(s) - lac repressor , fragment (logic) , repressor , chemistry , biology , computational biology , genetics , computer science , gene , algorithm , transcription factor
An early, spontaneous amber mutation in thelac i -gene allows translational reinitiation, which results in a mutantlac repressor. Comparison of the amino-terminal sequence of this mutant repressor with the partial amino-acid sequence of the wild-typelac repressor shows that reinitiation occurs at the first internal AUG codon, and results in a mutant protein lacking 42 residues at the amino-terminal end. This protein binds the inducer isopropyl-β-D-thiogalactoside with normal affinity, and is capable of maintaining a tetrameric structure; however, it does not repressin vivo . These data suggest that the amino-terminal portion of the wild-typelac repressor is necessary either for direct binding to thelac operator or for the correct conformation for binding to DNA.