title: Requirement for an A-tract structure at the binding site of phage phi 29 transcriptional activator.
abstract: The Bacillus subtilis phage phi 29 transcriptional activator, protein p4, binds to the 5'-AACT-TTTT-15 base-pair spacer-AAAATGTT-3' inverted repeat. In this communication, we study the influence in protein p4 binding of the DNA helical structure within the protein p4 recognition sequences, 5'-AAAATAG-3'. Protein p4 could efficiently bind to a modified target in which the A-tracts had been changed into T-tracts (a different sequence with a similar structure). Binding was lost when the structure of the binding site was modified by an interrupting C residue. The results suggest that the DNA helical structure of the A-tracts is critical for p4 binding. Two models are described that would explain how protein p4 recognized its target sequences on the DNA.
authors.affiliation: Centro de Biología Molecular, Severo Ochoa, (CSIC-UAM), Universidad Autónoma, Cantoblanco, Madrid, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Nuez
authors.forename: F
authors.initials: F
authors.lastname: Rojo
authors.forename: M
authors.initials: M
authors.lastname: Salas
mesh_terms: D017103:Bacillus Phages / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic; D015534:Trans-Activators / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D015534:Trans-Activators