Petasiphenol:  A DNA Polymerase λ Inhibitor

• Published in: Biochemistry (Easton) 2002-12, Vol.41 (49), p.14463-14471
• Main Authors: Mizushina, Yoshiyuki, Kamisuki, Shinji, Kasai, Nobuyuki, Ishidoh, Tomomi, Shimazaki, Noriko, Takemura, Masaharu, Asahara, Hitomi, Linn, Stuart, Yoshida, Shonen, Koiwai, Osamu, Sugawara, Fumio, Yoshida, Hiromi, Sakaguchi, Kengo
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antimutagenic Agents - chemistry; Antimutagenic Agents - isolation & purification; Antimutagenic Agents - pharmacology; Binding Sites; BRCA1 Protein - chemistry; Caffeic Acids - chemistry; Caffeic Acids - isolation & purification; Caffeic Acids - pharmacology; Cattle; Computer Simulation; DNA Polymerase beta - antagonists & inhibitors; DNA Polymerase beta - chemistry; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - isolation & purification; Enzyme Inhibitors - pharmacology; HeLa Cells; Humans; Models, Molecular; Molecular Sequence Data; Peptide Fragments - chemistry; Petasites - chemistry; Protein Structure, Tertiary; Rats; Sequence Homology, Amino Acid
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi020476q

Petasiphenol, a bio-antimutagen isolated from a Japanese vegetable, Petasites japonicus, selectively inhibits the activities of mammalian DNA polymerase λ (pol λ) in vitro. The compound did not influence the activities of replicative DNA polymerases such as α, δ, and ε but also showed no effect even on the pol β activity, the three-dimensional structure of which is thought to be highly similar to pol λ. The inhibitory effect of petasiphenol on intact pol λ including the BRCA1 C-terminus (BRCT) domain was dose-dependent, and 50% inhibition was observed at a concentration of 7.8 μM. The petasiphenol-induced inhibition of the pol λ activity was noncompetitive with respect to both the DNA template-primer and the dNTP substrate. Petasiphenol did not only inhibit the activity of the truncated pol λ including the pol β-like core, in which the BRCT motif was deleted in its N-terminal region. BIAcore analysis demonstrated that petasiphenol bound selectively to the N-terminal domain of pol λ but did not bind to the C-terminal region. On the basis of these results, the pol λ inhibitory mechanism of petasiphenol is discussed.