Nitroxide-labeled pyrimidines for non-covalent spin-labeling of abasic sites in DNA and RNA duplexes

2014 ◽  
Vol 12 (37) ◽  
pp. 7366-7374 ◽  
Author(s):  
Sandip A. Shelke ◽  
Gunnar B. Sandholt ◽  
Snorri Th. Sigurdsson

Of ten new pyrimidine-derived nitroxide spin labels, an N1-ethylamino triazole-linked uracil derivative binds fully to both DNA and RNA duplexes containing an abasic site, as determined by CW-EPR.

2019 ◽  
Vol 48 (2) ◽  
pp. 924-933 ◽  
Author(s):  
Marcel Heinz ◽  
Nicole Erlenbach ◽  
Lukas S Stelzl ◽  
Grace Thierolf ◽  
Nilesh R Kamble ◽  
...  

Abstract Pulsed electron paramagnetic resonance (EPR) experiments, among them most prominently pulsed electron-electron double resonance experiments (PELDOR/DEER), resolve the conformational dynamics of nucleic acids with high resolution. The wide application of these powerful experiments is limited by the synthetic complexity of some of the best-performing spin labels. The recently developed $\bf\acute{G}$ (G-spin) label, an isoindoline-nitroxide derivative of guanine, can be incorporated non-covalently into DNA and RNA duplexes via Watson-Crick base pairing in an abasic site. We used PELDOR and molecular dynamics (MD) simulations to characterize $\bf\acute{G}$, obtaining excellent agreement between experiments and time traces calculated from MD simulations of RNA and DNA double helices with explicitly modeled $\bf\acute{G}$ bound in two abasic sites. The MD simulations reveal stable hydrogen bonds between the spin labels and the paired cytosines. The abasic sites do not significantly perturb the helical structure. $\bf\acute{G}$ remains rigidly bound to helical RNA and DNA. The distance distributions between the two bound $\bf\acute{G}$ labels are not substantially broadened by spin-label motions in the abasic site and agree well between experiment and MD. $\bf\acute{G}$ and similar non-covalently attached spin labels promise high-quality distance and orientation information, also of complexes of nucleic acids and proteins.


2020 ◽  
Vol 85 (6) ◽  
pp. 4036-4046 ◽  
Author(s):  
Haraldur Y. Juliusson ◽  
Snorri Th. Sigurdsson

2011 ◽  
Vol 83 (3) ◽  
pp. 677-686 ◽  
Author(s):  
Snorri Th. Sigurdsson

Electron paramagnetic resonance (EPR) spectroscopy has increasingly been applied for the study of nucleic acid structure and dynamics. Such studies require incorporation of free radicals (spin labels) into the biopolymer. The labels can be incorporated during chemical synthesis of the oligomer (phosphoramidite approach) or postsynthetically, by reaction of a spin-labeling reagent with a reactive functional group on the oligonucleotide. Incorporation of the rigid nitroxide spin label Ç is an example of the phosphoramidite method, and reaction of a spin-labeled azide with an alkyne-modified oligomer to yield a triazole-derived, spin-labeled nucleotide illustrates the postsynthetic spin-labeling strategy. Characterization and application of these labels to study structural features of DNA by EPR spectroscopy is discussed. Finally, a new spin-labeling strategy is described for nucleic acids that relies on noncovalent interactions between a spin-labeled nucleobase and an abasic site in duplex DNA.


2019 ◽  
Vol 17 (7) ◽  
pp. 1805-1808 ◽  
Author(s):  
Christof Domnick ◽  
Gregor Hagelueken ◽  
Frank Eggert ◽  
Olav Schiemann ◽  
Stephanie Kath-Schorr

Spin labeling of in vitro transcribed RNA by iEDDA click chemistry is demonstrated. This allows the determination of distance distributions between two nitroxide spin labels by PELDOR in a self-complementary RNA duplex.


Author(s):  
Hannah Russell ◽  
Rachel Stewart ◽  
Christopher Prior ◽  
Vasily S. Oganesyan ◽  
Thembaninkosi G. Gaule ◽  
...  

AbstractIn the study of biological structures, pulse dipolar spectroscopy (PDS) is used to elucidate spin–spin distances at nanometre-scale by measuring dipole–dipole interactions between paramagnetic centres. The PDS methods of Double Electron Electron Resonance (DEER) and Relaxation Induced Dipolar Modulation Enhancement (RIDME) are employed, and their results compared, for the measurement of the dipolar coupling between nitroxide spin labels and copper-II (Cu(II)) paramagnetic centres within the copper amine oxidase from Arthrobacter globiformis (AGAO). The distance distribution results obtained indicate that two distinct distances can be measured, with the longer of these at c.a. 5 nm. Conditions for optimising the RIDME experiment such that it may outperform DEER for these long distances are discussed. Modelling methods are used to show that the distances obtained after data analysis are consistent with the structure of AGAO.


2021 ◽  
Vol 7 (17) ◽  
pp. eabf6106
Author(s):  
Weiwei He ◽  
Yen-Lin Chen ◽  
Lois Pollack ◽  
Serdal Kirmizialtin

Double-stranded DNA (dsDNA) and RNA (dsRNA) helices display an unusual structural diversity. Some structural variations are linked to sequence and may serve as signaling units for protein-binding partners. Therefore, elucidating the mechanisms and factors that modulate these variations is of fundamental importance. While the structural diversity of dsDNA has been extensively studied, similar studies have not been performed for dsRNA. Because of the increasing awareness of RNA’s diverse biological roles, such studies are timely and increasingly important. We integrate solution x-ray scattering at wide angles (WAXS) with all-atom molecular dynamics simulations to explore the conformational ensemble of duplex topologies for different sequences and salt conditions. These tightly coordinated studies identify robust correlations between features in the WAXS profiles and duplex geometry and enable atomic-level insights into the structural diversity of DNA and RNA duplexes. Notably, dsRNA displays a marked sensitivity to the valence and identity of its associated cations.


2010 ◽  
Vol 30 (13) ◽  
pp. 3206-3215 ◽  
Author(s):  
Nayun Kim ◽  
Sue Jinks-Robertson

ABSTRACT Abasic (AP) sites are potent blocks to DNA and RNA polymerases, and their repair is essential for maintaining genome integrity. Although AP sites are efficiently dealt with through the base excision repair (BER) pathway, genetic studies suggest that repair also can occur via nucleotide excision repair (NER). The involvement of NER in AP-site removal has been puzzling, however, as this pathway is thought to target only bulky lesions. Here, we examine the repair of AP sites generated when uracil is removed from a highly transcribed gene in yeast. Because uracil is incorporated instead of thymine under these conditions, the position of the resulting AP site is known. Results demonstrate that only AP sites on the transcribed strand are efficient substrates for NER, suggesting the recruitment of the NER machinery by an AP-blocked RNA polymerase. Such transcription-coupled NER of AP sites may explain previously suggested links between the BER pathway and transcription.


2013 ◽  
Vol 639 (8-9) ◽  
pp. 1655-1660 ◽  
Author(s):  
Christopher Polonyi ◽  
Ingrid Albertsson ◽  
Mariana S. Damian ◽  
Sofi K. C. Elmroth
Keyword(s):  

2016 ◽  
Vol 2016 ◽  
pp. 1-4
Author(s):  
Chun Wu

Biotinylation of deoxyguanosine at an abasic site in double-stranded oligodeoxynucleotides was studied. The biotinylation of deoxyguanosine is achieved by copper-catalyzed click reaction after the conjugation of the oligodeoxynucleotide with 2-oxohex-5-ynal. The biotinylation enables visualization of the biotinylated oligodeoxynucleotides by chemiluminescence on a nylon membrane. In order to investigate the biotinylated site, the biotinylated oligodeoxynucleotides were amplified by the DNA polymerase chain reaction. Replacement of guanine opposing the abasic site with adenine generated by the activity of the terminal deoxynucleotidyl transferase of DNA polymerase was detected by DNA sequencing analysis and restriction endonuclease digestion. This study suggests that 2-oxohex-5-ynal may be useful for the detection of the unpaired deoxyguanosine endogenously generated at abasic sites in genomic DNA.


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