title: Catalytic sites for 3' and 5' incision of Escherichia coli nucleotide excision repair are both located in UvrC.
abstract: 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.
authors.affiliation: Laboratory of Molecular Genetics, Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
authors.forename: E E
authors.initials: EE
authors.lastname: Verhoeven
authors.forename: M
authors.initials: M
authors.lastname: van Kesteren
authors.forename: G F
authors.initials: GF
authors.lastname: Moolenaar
authors.forename: R
authors.initials: R
authors.lastname: Visse
authors.forename: N
authors.initials: N
authors.lastname: Goosen
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D020134:Catalytic Domain; D004260:DNA Repair; D004269:DNA, Bacterial; D004706:Endodeoxyribonucleases; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D004706:Endodeoxyribonucleases; C066567:UvrC protein, E coli