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Closed Access item A new protein domain for binding to DNA through the minor groove

Authors:Freire, Raimundo
Salas, Margarita
Hermoso, José Miguel
Keywords:DNA minor groove binding, DNA replication, Phage ø29
Issue Date:15-Sep-1994
Publisher:Nature Publishing Group
Citation:Embo Journal 13(18):4353-360 (1994)
Abstract:Protein p6 of the Bacillus subtilis phage phi 29 binds with low sequence specificity to DNA through the minor groove, forming a multimeric nucleoprotein complex that activates the initiation of phi 29 DNA replication. Deletion analysis suggested that the N-terminal part of protein p6, predicted to form an amphipathic alpha-helix, is involved in DNA binding. We have constructed site-directed mutants at the polar side of the putative alpha-helix. DNA binding and activation of initiation of phi 29 DNA replication were impaired in most of the mutant proteins obtained. A 19 amino acid peptide comprising the N-terminus of protein p6 interacted with a DNA fragment containing high-affinity signals for protein p6 binding with approximately 50-fold higher affinity than the peptide corresponding to an inactive mutant. Both wild-type peptide and protein p6 recognized the same sequences in this DNA fragment. This result, together with distamycin competition experiments, suggested that the wild-type peptide also binds to DNA through the minor groove. In addition, CD spectra of the wild-type peptide showed an increase in the alpha-helical content when bound to DNA. All these results indicate that an alpha-helical structure located in the N-terminal region of protein p6 is involved in DNA binding through the minor groove.
Publisher version (URL):http://www.ncbi.nlm.nih.gov/pmc/articles/pmid/7925279/?tool=pubmed
E-ISSNmetadata.dc.identifier.doi = DOI:1460-2075
Appears in Collections:(CBM) Artículos

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