Dissociation Dynamics of XPC-RAD23B from Damaged DNA Is a Determining Factor of NER Efficiency.
XPC-RAD23B (XPC) plays a critical role in human nucleotide excision repair (hNER) as this complex recognizes DNA adducts to initiate NER. To determine the mutagenic potential of structurally different bulky DNA damages, various studies have been conducted to define the correlation of XPC-DNA damage equilibrium binding affinity with NER efficiency. However, little is known about the effects of XPC-DNA damage recognition kinetics on hNER. Although association of XPC is important, our current work shows that the XPC-DNA dissociation rate also plays a pivotal role in achieving NER efficiency. We characterized for the first time the binding of XPC to mono- versus di-AAF-modified sequences by using the real time monitoring surface plasmon resonance technique. Strikingly, the half-life (t1/2 or the retention time of XPC in association with damaged DNA) shares an inverse relationship with NER efficiency. This is particularly true when XPC remained bound to clustered adducts for a much longer period of time as compared to mono-adducts. Our results suggest that XPC dissociation from the damage site could become a rate-limiting step in NER of certain types of DNA adducts, leading to repression of NER.
Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, 37614, United States of America.
Benjamin
B
Hilton
Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island, 02881, United States of America.
Sathyaraj
S
Gopal
Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island, 02881, United States of America.
Lifang
L
Xu
Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, 37614, United States of America.
Sharmistha
S
Mazumder
Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, 37614, United States of America.
Phillip R
PR
Musich
Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island, 02881, United States of America.
Bongsup P
BP
Cho
Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, 37614, United States of America.
Yue
Y
Zou
D000251:Adenosine Triphosphatases / Q000378:metabolism; D001483:Base Sequence; D004247:DNA / Q000378:metabolism; D018736:DNA Adducts / Q000378:metabolism; D004249:DNA Damage; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000378:metabolism; D006207:Half-Life; D006367:HeLa Cells; D006801:Humans; D008954:Models, Biological; D009691:Nucleic Acid Denaturation; D011485:Protein Binding; D013379:Substrate Specificity; D013816:Thermodynamics
D018736:DNA Adducts; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C513287:RAD23B protein, human; C086984:XPC protein, human; D004247:DNA; C068631:UvrA protein, E coli; D000251:Adenosine Triphosphatases; D045643:DNA Repair Enzymes