Verhoeven E E, van Kesteren M, Moolenaar G F, Visse R, Goosen N
Laboratory of Molecular Genetics, Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
J Biol Chem. 2000 Feb 18;275(7):5120-3. doi: 10.1074/jbc.275.7.5120.
Nucleotide excision repair in Escherichia coli is a multistep process in which DNA damage is removed by incision of the DNA on both sides of the damage, followed by removal of the oligonucleotide containing the lesion. The two incision reactions take place in a complex of damaged DNA with UvrB and UvrC. It has been shown (Lin, J. -J., and Sancar, A. (1992) J. Biol. Chem. 267, 17688-17692) that the catalytic site for incision on the 5' side of the damage is located in the UvrC protein. Here we show that the catalytic site for incision on the 3' side is in this protein as well, because substitution R42A abolishes 3' incision, whereas formation of the UvrBC-DNA complex and the 5' incision reaction are unaffected. Arg(42) is part of a region that is homologous to the catalytic domain of the homing endonuclease I-TevI. We propose that the UvrC protein consists of two functional parts, with the N-terminal half for the 3' incision reaction and the C-terminal half containing all the determinants for the 5' incision reaction.
大肠杆菌中的核苷酸切除修复是一个多步骤过程，其中通过在损伤两侧切割DNA来去除DNA损伤，随后去除包含损伤的寡核苷酸。这两个切割反应发生在受损DNA与UvrB和UvrC形成的复合物中。已有研究表明（Lin, J. -J., and Sancar, A. (1992) J. Biol. Chem. 267, 17688 - 17692），损伤5'侧的切割催化位点位于UvrC蛋白中。在此我们表明，损伤3'侧的切割催化位点也在该蛋白中，因为R42A取代消除了3'切割，而UvrBC - DNA复合物的形成和5'切割反应不受影响。精氨酸（42）是与归巢内切酶I - TevI催化结构域同源的区域的一部分。我们提出，UvrC蛋白由两个功能部分组成，N端一半用于3'切割反应，C端一半包含5'切割反应的所有决定因素。
