Petasiphenol, a bio-antimutagen isolated from a Japanese vegetable,
Petasites japonicus,selectively inhibits the activities of mammalian DNA polymerase
![](/images/gifchars/lambda.gif)
(pol
![](/images/gifchars/lambda.gif)
) in vitro. The compound didnot influence the activities of replicative DNA polymerases such as
![](/images/gifchars/alpha.gif)
,
![](/images/gifchars/delta.gif)
, and
![](/images/gifchars/epsilon.gif)
but also showed no effecteven on the pol
![](/images/gifchars/beta2.gif)
activity, the three-dimensional structure of which is thought to be highly similar to pol
![](/images/gifchars/lambda.gif)
. The inhibitory effect of petasiphenol on intact pol
![](/images/gifchars/lambda.gif)
including the BRCA1 C-terminus (BRCT) domainwas dose-dependent, and 50% inhibition was observed at a concentration of 7.8
![](/images/entities/mgr.gif)
M. The petasiphenol-induced inhibition of the pol
![](/images/gifchars/lambda.gif)
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
![](/images/gifchars/lambda.gif)
includingthe pol
![](/images/gifchars/beta2.gif)
-like core, in which the BRCT motif was deleted in its N-terminal region. BIAcore analysisdemonstrated that petasiphenol bound selectively to the N-terminal domain of pol
![](/images/gifchars/lambda.gif)
but did not bind tothe C-terminal region. On the basis of these results, the pol
![](/images/gifchars/lambda.gif)
inhibitory mechanism of petasiphenol isdiscussed.