Photo-controlled binding of MutS to photo-caged DNA duplexes incorporating 4- O -(2-nitrobenzyl) or 4- O -[2-(2-nitrophenyl)propyl]thymidine

Paul

et al. 2021

RSC Chem. Biol.

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Light-induced modulation of DNA recognition by the Rad4/XPC damage sensor protein

Paul

et al. 2021

RSC Chem. Biol.

“…For instance, such chemistry has been used in DNA for inducing site-specific, single or double strand breaks [65][66][67] and for triggering structural transition in a base excision repair enzyme to study its mechanism 42 . NPOM-related, 2-nitrobenzyl or 2-(2nitrophenyl)propyl groups have also been shown to mask the recognition of mismatches by the mismatch binding protein MutS, which photo-irradiation could restore 68 . Here in this study, we show for the first time that a photoswitchable modification on DNA can be recognized as efficiently as a bona fide DNA lesion by a DNA damage sensor, the Rad4/XPC nucleotide excision repair complex.…”

Section: Discussionmentioning

confidence: 99%

Light-induced modulation of DNA recognition by the Rad4/XPC damage sensor protein

Paul

et al. 2020

Preprint

Biomolecular structural changes upon binding/unbinding are key to their functions. However, characterization of such dynamical processes with high spatial and temporal resolutions is difficult as it requires ways to rapidly trigger the assembly/disassembly as well as ways to monitor the structural changes over time. Recently, various chemical strategies have been developed to use light to trigger changes in oligonucleotide structures, thereby their activities. Here we report that photoswitchable DNA can be used to modulate the DNA binding of the Rad4/XPC DNA repair complex using light. Rad4/XPC specifically binds to diverse helix-destabilizing/distorting lesions including bulky organic adducts and functions as a key initiator for the eukaryotic nucleotide excision repair (NER) pathway. We show that the 6-nitropiperonyloxymethyl (NPOM)-modified DNA is recognized by the Rad4 protein as a specific substrate and that the specific binding can be abolished by light-induced cleavage of the NPOM group from DNA in a dose-dependent manner. Fluorescence lifetime-based analyses of the DNA conformations suggest that free NPOM-DNA retains B-DNA-like conformations despite its bulky NPOM adduct, but Rad4-binding renders it to be heterogeneously distorted. Subsequent extensive conformational searches and molecular dynamics simulations demonstrate that NPOM in DNA can be housed in the major groove of the DNA, with stacking interactions among the nucleotide pairs remaining largely unperturbed and thus retaining overall B-DNA conformation. Our work suggests that photoactivable DNA can be used as a DNA lesion surrogate to study DNA repair mechanisms such as nucleotide excision repair.Abstract FigureGraphical SummaryThis work shows that a photolabile 6-nitropiperonyloxymethyl (NPOM)-modified DNA is specifically recognized by the Rad4/XPC damage sensor protein complex that initiates the nucleotide excision repair pathway; light-induced cleavage of NPOM abolishes the specific binding to Rad4/XPC.

“…NPP-dT and NPE-dT were used to block the binding of the MutS mismatch repair protein to a DNA bulge, which then could be removed by photoirradiation and enable the binding. 63 NPP, NPE, and oNB linkers were also widely used as photocleavable linkers in the backbone of oligonucleotides to control gene expression and editing. For instance, NPE has been utilized in modulating siRNA activity.…”

Section: Photochemical Modifications For Dna/ Rna Oligonucleotidesmentioning

confidence: 99%

“…NPP-dT and NPE-dT were used to block the binding of the MutS mismatch repair protein to a DNA bulge, which then could be removed by photoirradiation and enable the binding. 63 …”

Section: Photochemical Modifications For Dna/rna Oligonucleotidesmentioning

confidence: 99%

Photochemical modifications for DNA/RNA oligonucleotides

Min

2022

RSC Adv.