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Receipt of the C-terminal tail from a neighboring lambda Int protomer allosterically stimulates Holliday junction resolution.
Hazelbaker, Dane; Radman-Livaja, Marta; Landy, Arthur.
Afiliación
  • Hazelbaker D; Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, USA.
J Mol Biol ; 351(5): 948-55, 2005 Sep 02.
Article en En | MEDLINE | ID: mdl-16054645
Bacteriophage lambda integrase (Int) catalyzes the integration and excision of the phage lambda chromosome into and out of the Esherichia coli host chromosome. The seven carboxy-terminal residues (C-terminal tail) of Int comprise a context-sensitive regulatory element that links catalytic function with protein multimerization and also coordinates Int functions within the multimeric recombinogenic complex. The experiments reported here show that the beta5-strand of Int is not simply a placeholder for the C-terminal tail but rather exerts its own allosteric effects on Int function in response to the incoming tail. Using a mutant integrase in which the C-terminal tail has been deleted (W350ter), we demonstrate that the C-terminal tail is required for efficient and accurate resolution of Holliday junctions by tetrameric Int. Addition of a free heptameric peptide of the same sequence as the C-terminal tail partially reverses the W350ter defects by stimulating Holliday junction resolution. The peptide also stimulates the topoisomerase function of monomeric W350ter. Single residue alterations in the peptide sequence and a mutant of the beta5 strand indicate that the observed stimulation arises from specific contacts with the beta5 strand (residues 239-243). The peptide does not stimulate binding of W350ter to its cognate DNA sites and therefore appears to recapitulate the effects of the normal C-terminal tail intermolecular contacts in wild-type Int. Models for the allosteric stimulation of Int activity by beta5 strand contacts are discussed.
Asunto(s)

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Recombinación Genética / Bacteriófago lambda / Integrasas Tipo de estudio: Prognostic_studies Idioma: En Revista: J Mol Biol Año: 2005 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Países Bajos

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Recombinación Genética / Bacteriófago lambda / Integrasas Tipo de estudio: Prognostic_studies Idioma: En Revista: J Mol Biol Año: 2005 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Países Bajos