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Updated: Jul 18, 2026

Atomic Force Microscopy Investigations of DNA Lesion Recognition in Nucleotide Excision Repair
Published on: May 24, 2017
Inhibition of restriction enzyme's DNA sequence recognition by PUVA treatment
F Hanawa1, M Okamoto, G H Towers
1Forestry and Forest Products Research Institute (FFPRI), P.O. Box 16, Tsukuba, Ibaraki 305-8687, Japan. fujinori@ffpri.affrc.go.jp
Abstract:
Applying various restriction enzymes on a specially designed 1.5 kb DNA fragment revealed that the inhibitory effects of psoralens + UVA irradiation (PUVA) treatment on restriction endonuclease activities are caused by recognition inhibition. In this study restriction enzymes that have a 5'-TpA sequence at the cleaving site (KpnI, XbaI, PmeI and DraI), and the noncleaving site (PacI) in recognition sites, or have two 5'-TpA sequences at the recognition site, and a nonspecific sequence between the recognition and the cleaving sites (BciVI), were inhibited by PUVA treatment. Most of the other restriction enzymes used in this study, which do not have a 5'-TpA sequence at their restriction site, were not inhibited by PUVA treatment, although a 5'-TpA sequence is located adjacent (SmaI) or very close (BamHI, SacI and PstI) to the recognition and cleaving sites for these enzymes. Because SphI, which does not have 5'-TpA at its restriction site, was strongly inhibited by PUVA treatment, the 5'-CpA sequence is suggested to be a new binding site of psoralens after UVA irradiation.
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