title: Podophyllotoxin directly binds a hinge domain in E2 of HPV and inhibits an E2/E7 interaction in vitro.
abstract: Podophyllotoxin (PT), a strong cytotoxic agent from berberidaceae, has been known to inhibit tubulin polymerization. Although PT has been used for developing anticancer drugs as one of seed compounds, clinical treatment by itself has been unsuccessful because of the side effects, except one example in the treatments of warts. In this study, we screened peptides binding to PT with T7 phage display clonings in order to obtain more information about molecular mechanism of the action. A selected phage clone has a specific amino acid sequence to be SVPSRRRPDGRTHRSSRG. A homology search by protein database BLAST showed that this sequence had a similarity to a hinge domain (HD) of E2 protein in human papillomavirus (HPV) type 1a which is known to cause plantar warts. Surface plasmon resonance (SPR) analysis showed that PT bound to a recombinant HPV 1a E2 protein giving a K(D)=24.1microM which has compared with those of other domains of E2 protein. Also we demonstrated whether PT inhibited HD interaction or not. E7 protein of HPV has been known to be an oncoprotein and was reported to interact with HD of E2 protein. We demonstrated that an E2/E7 interaction was inhibited by the addition of PT in this report. And we showed the bindings of PT to other types of HPV. Our results suggest that PT is potential as a tool for clarifying the molecular mechanism of HPV.
authors.affiliation: Genome and Drug Research Center, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8501, Japan.
authors.forename: Takeki
authors.initials: T
authors.lastname: Saitoh
authors.forename: Kouji
authors.initials: K
authors.lastname: Kuramochi
authors.forename: Takahiko
authors.initials: T
authors.lastname: Imai
authors.forename: Kei-ichi
authors.initials: K
authors.lastname: Takata
authors.forename: Masahide
authors.initials: M
authors.lastname: Takehara
authors.forename: Susumu
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Kengo
authors.initials: K
authors.lastname: Sakaguchi
authors.forename: Fumio
authors.initials: F
authors.lastname: Sugawara
mesh_terms: D000818:Animals; D001665:Binding Sites; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000187:drug effects* / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D051379:Mice; D008968:Molecular Conformation; D009856:Oncogene Proteins, Viral / Q000737:chemistry* / Q000187:drug effects* / Q000235:genetics; D050725:Papillomavirus E7 Proteins; D019151:Peptide Library; D011034:Podophyllotoxin / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary / Q000187:drug effects; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013997:Time Factors
chemical_list: D004268:DNA-Binding Proteins; C493190:E7 protein, human papillomavirus 11; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D019151:Peptide Library; C076036:oncogene protein E2, Human papillomavirus type 1; C059731:oncogene protein E7, Human papillomavirus type 16; D011034:Podophyllotoxin