Modulation of UvrD Helicase Activity by Covalent DNA-Protein Cross-links
Year: 2010
Type: article
Abstract: UvrD (DNA helicase II) has been implicated in DNA replication, DNA recombination, nucleotide excision repair, and methyl-directed mismatch repair. The enzymatic function of UvrD is to translocate along a DNA strand in a 3' to 5' direction and unwind duplex DNA utilizing a DNA-dependent ATPase activity. In addition, UvrD interacts with many other proteins involved in the above processes and is hypothesized to facilitate protein turnover, thus promoting further DNA processing. Although UvrD interactions with proteins bound to DNA have significant biological implications, the effects of covalent DNA-protein cross-links on UvrD helicase activity have not been characterized. Herein, we demonstrate that UvrD-catalyzed strand separation was inhibited on a DNA strand to which a 16-kDa protein was covalently bound. Our sequestration studies suggest that the inhibition of UvrD activity is most likely due to a translocation block and not helicase sequestration on the cross-link-containing DNA substrate. In contrast, no inhibition of UvrD-catalyzed strand separation was apparent when the protein was linked to the complementary strand. The latter result is surprising given the earlier observations that the DNA in this covalent complex is severely bent ( approximately 70 degrees ), with both DNA strands making multiple contacts with the cross-linked protein. In addition, UvrD was shown to be required for replication of plasmid DNAs containing covalent DNA-protein complexes. Combined, these data suggest a critical role for UvrD in the processing of DNA-protein cross-links.
Source: Journal of Biological Chemistry
Institution: Oregon Health & Science University
Language: English
Topic: DNA Repair Mechanisms
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
Awards: Cellular responses to DNA-protein crosslinks, Novel Targets in Cancer Chemotherapy: Chemical Biology of Guanine Alkylation, BASE FLIPPING AND DNA DAMAGE RECOGNITION, Chemistry and Biology of Carcinogen-DNA Adducts, Discovery and development of OGG1 activators as precision drugs for modification of Alzheimer's disease progression.
OpenAlex ID: W1967184687