Characterization of the bacteriophage lambda excisionase (Xis) protein: The C-terminus is required for Xis - integrase cooperativity but not for DNA binding

Thomas E. Numrych, Richard I. Gumport, Jeffrey F. Gardner

Research output: Contribution to journalArticlepeer-review

Abstract

We have performed a mutational analysis of the xis gene of bacteriophage λ. The Xis protein is 72 amino acids in length and required for excisive recombination. Twentysix mutants of Xis were isolated that were impaired or deficient in λ excision. Mutant proteins that contained amino acid substitutions in the N-terminal 49 amino acids of Xis were defective in excisive recombination and were unable to bind DNA. In contrast, one mutant protein containing a leucine to proline substitution at position 60 and two truncated proteins containing either the N-terminal 53 or 64 amino acids continued to bind λ DNA, interact cooperatively with FIS and promote excision. However, these three mutants were unable to bind DNA cooperatively with Int. Cooperativity between wild-type Xis and Int required the presence of FIS, but not the Int core-type binding sites. This study shows that Xis has at least two functional domains and also demonstrates the importance of the cooperativity in DNA binding of FIS, Xis and Int in λ excision.

Original languageEnglish (US)
Pages (from-to)3797-3808
Number of pages12
JournalEMBO Journal
Volume11
Issue number10
StatePublished - Oct 1992

Keywords

  • Cooperativity
  • DNA binding
  • Mutagenesis
  • Recombination

ASJC Scopus subject areas

  • General Neuroscience
  • Molecular Biology
  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology

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