Publication Date: 2011.
Background: Human papillomavirus (HPV) is the main causative agent of cervical cancer, particularly high risk strains such us HPV-16, -18 and -31. The viral encoded E2 protein acts as a transcriptional modulator and exerts a key role in viral DNA replication. Thus, E2 constitutes an attractive target for developing antiviral agents. E2 is a homodimeric protein that interacts with the DNA target through an α-helix of each monomer. However, a peptide corresponding to the DNA recognition helix of HPV-16 E2 binds DNA with lower affinity than its full-length DNA binding domain. Therefore, in an attempt to promote the DNA binding of the isolated peptide, we have designed a conjugate compound of the E2 α-helix peptide and a derivative of the antibiotic distamycin, which involves simultaneous minor- and major-groove interactions. Methodology/Principal Findings: An E2 α-helix peptide-distamycin conjugate was designed and synthesized. It was characterized by NMR and CD spectroscopy, and its DNA binding properties were investigated by CD, DNA melting and gel shift experiments. The coupling of E2 peptide with distamycin does not affect its structural properties. The conjugate improves significantly the affinity of the peptide for specific DNA. In addition, stoichiometric amounts of specific DNA increase meaningfully the helical population of the peptide. The conjugate enhances the DNA binding constant 50-fold, maintaining its specificity. Conclusions/Significance: These results demonstrate that peptide-distamycin conjugates are a promising tool to obtain compounds that bind the E2 target DNA-sequences with remarkable affinity and suggest that a bipartite major/minor groove binding scaffold can be a useful approach for therapeutic treatment of HPV infection. © 2011 Wetzler et al.
Author affiliation: Wetzler, D.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Author affiliation: Comin, M.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Author affiliation: Gallo, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Keywords: distamycin A; DNA; peptide; protein E2; transcription factor; unclassified drug; antivirus agent; biomimetic material; distamycin A; DNA binding protein; E2 protein, Human papillomavirus type 16; oncoprotein; peptide fragment; pyrrole derivative; virus DNA; alpha helix; article; circular dichroism; computer model; conjugation; DNA synthesis; gel mobility shift assay; Human papillomavirus type 16; nonhuman; nuclear magnetic resonance spectroscopy; protein DNA binding; protein interaction; protein structure; amino acid sequence; chemical structure; chemistry; enzyme specificity; genetics; Human papillomavirus type 16; metabolism; molecular genetics; nucleotide sequence; papillomavirus infection; physiology; protein secondary structure; synthesis; Human papillomavirus; Human papillomavirus type 16; Amino Acid Sequence; Antiviral Agents; Base Sequence; Biomimetic Materials; Distamycins; DNA, Viral; DNA-Binding Proteins; Human papillomavirus 16; Models, Molecular; Molecular Sequence Data; Oncogene Proteins, Viral; Papillomavirus Infections; Peptide Fragments; Protein Structure, Secondary; Pyrroles; Substrate Specificity.
Repository: Biblioteca Digital (UBA-FCEN). Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales