Specificity in DNA recognition by a peptide from papillomavirus E2 protein.
The E2 proteins of papillomavirus specifically bind to double-stranded DNA containing the consensus sequence ACCG-N4-CGGT, where N is any nucleotide. Here, we show the binding and recognition of dissimilar DNA sequences by an 18 amino-acid peptide (alpha1E2), which corresponds to the DNA-recognition helix, alpha-helix-1. Isothermal DNA binding assays performed with the DNA consensus sequence show saturable curves with alpha1E2 peptide, and the alpha1E2 peptide is converted to an ordered conformation upon complexation. Measurements performed with non-specific DNA sequence fail to saturate, a behavior characteristic of non-specific binding. Binding of the alpha1E2 peptide to these DNA sequences display a different counter-ion dependence, indicating a dissimilar, sequence-dependent mechanism of interaction. Quantitative stoichiometric measurements revealed the specificity in alpha1E2 peptide recognition of the ACCG half-site, demonstrating capacity for discrimination of nucleic acid bases sequences without the need of a whole protein architecture.
Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, CCS, sala Bs-34, Ilha do Fundão, 21941-590, Rio de Janeiro, RJ, Brazil.
Joana
J
Faber-Barata
Ronaldo
R
Mohana-Borges
Luís Maurício T R
LM
Lima
D002942:Circular Dichroism; D016384:Consensus Sequence; D004247:DNA / Q000378:metabolism*; D009856:Oncogene Proteins, Viral / Q000737:chemistry / Q000378:metabolism*; D027383:Papillomaviridae / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation; D012965:Sodium Chloride / Q000494:pharmacology; D013379:Substrate Specificity
D009856:Oncogene Proteins, Viral; D010455:Peptides; D012965:Sodium Chloride; D004247:DNA