The C-terminal region of the Escherichia coli UvrC protein, which is homologous to the C-terminal region of the human ERCC1 protein, is involved in DNA binding and 5'-incision.
The incisions in the DNA at the 3'- and 5'-side of a DNA damage during nucleotide excision repair in Escherichia coli occur in a complex consisting of damaged DNA, UvrB and UvrC. The exact requirements for the two incision events, however, are different. It has previously been shown that the 3'-incision requires the interaction between the C-terminal domain of UvrB and a homologous region in UvrC. This interaction, however, is dispensable for the 5'-incision. Here we show that the C-terminal domain of the UvrC protein is essential for the 5'-incision, whereas this domain can be deleted without affecting the 3'-incision. The C-terminal domain of UvrC is homologous with the C-terminal part of the ERCC1 protein which, in a complex with XPF, is responsible for the 5'-incision reaction in human nucleotide excision repair. Both in the UvrC and the ERCC1 domain a Helix-hairpin-Helix (HhH) motif can be indicated, albeit at different positions. Such a motif also has been found in a large variety of DNA binding proteins and it has been suggested to form a structure involved in non-sequence-specific DNA binding. In contrast to the full length UvrC protein, a truncated UvrC protein (UvrC554) lacking the entire ERCC1 homology including the HhH motif no longer binds to ssDNA. Analysis of protein-DNA complexes using bandshift experiments showed that this putative DNA binding domain of UvrC is required for stabilisation of the UvrBC-DNA complex after the 3'-incision has taken place. We propose that after the initial 3'-incision the HhH motif recognises a specific DNA structure, thereby positioning the catalytic site for the subsequent 5'-incision reaction.
Moolenaar
G F
GF
Laboratory of Molecular Genetics, Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, PO Box 9502, 2300 RA Leiden, The Netherlands.
Uiterkamp
R S
RS
Zwijnenburg
D A
DA
Goosen
N
N
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D001665:Binding Sites; D004247:DNA / Q000378:metabolism*; D004260:DNA Repair; D004277:DNA, Single-Stranded / Q000378:metabolism; D004268:DNA-Binding Proteins; D004706:Endodeoxyribonucleases; D004720:Endonucleases; D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D011506:Proteins / Q000737:chemistry* / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017385:Sequence Homology; D013329:Structure-Activity Relationship
D001426:Bacterial Proteins; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D010446:Peptide Fragments; D011506:Proteins; D011993:Recombinant Fusion Proteins; D004247:DNA; C071447:ERCC1 protein, human; D004706:Endodeoxyribonucleases; D004720:Endonucleases; C066567:UvrC protein, E coli