The origin of spontaneous point mutations in DNA via Löwdin mechanism of proton tunneling in DNA base pairs: Cure with covalent base pairing*

2002 ◽  
Vol 90 (2) ◽  
pp. 910-923 ◽  
Author(s):  
Eugene S. Kryachko
2003 ◽  
Vol 14 (01) ◽  
pp. 133-156 ◽  
Author(s):  
V. L. GOLO ◽  
YU. S. VOLKOV

We study the interplay of the tautomeric transitions amino/keto → imino/enol of DNA base pairs and the elastic properties of the DNA, by employing the numerical simulation of the nonlinear and nonlocal Schrödinger equation that describes the concerted tunneling of protons in the hydrogen bonds of base pairs. We show that the dynamics of tunneling is characterized by solitary waves for the tunneling amplitudes. The velocity of solitons is generally small, of the order 10-3–10-2 cm/sec . We also found a phenomenon similar to the freak wave of nonlinear theory; in the context of DNA, it means that the conformation of the base pairs and the proton states, for which a tautomeric transition is only of low probability, could move along the DNA molecule and focus on a smaller set of base pairs so that the rate of transition increases. This result may have a bearing on the phenomenon of spontaneous mutations. We suggest that the irradiation of DNA with electromagnetic waves at frequencies in the infrared region, corresponding to the proton tunneling, could cause mutations.


2020 ◽  
Vol 17 (2) ◽  
pp. 124-137 ◽  
Author(s):  
Adel Mahmoud Attia ◽  
Ahmed Ibrahin Khodair ◽  
Eman Abdelnasser Gendy ◽  
Mohammed Abu El-Magd ◽  
Yaseen Ali Mosa Mohamed Elshaier

Background:Perturbation of nucleic acids structures and confirmation by small molecules through intercalation binding is an intriguing application in anticancer therapy. The planar aromatic moiety of anticancer agents was inserted between DNA base pairs leading to change in the DNA structure and subsequent functional arrest.Objective:The final scaffold of the target compounds was annulated and linked to a benzotriazole ring. These new pharmacophoric features were examined as antiviral and anticancer agents against MCF7 and their effect on DNA damage was also assessed.Methods:A new series of fully substituted 2-oxopyridine/2-thioxopyridine derivatives tethered to a benzotriazole moiety (4a-h) was synthesized through Michael cyclization of synthesized α,β- unsaturated compounds (3a-e) with appropriate active methylene derivatives. The DNA damage study was assessed by comet assay. In silico DNA molecular docking was performed using Open Eye software to corroborate the experimental results and to understand molecule interaction at the atomic level.Results:The highest DNA damage was observed in Doxorubicin, followed by 4h, then, 4b, 4g, 4f, 4e, and 4d. The docking study showed that compound 4h formed Hydrogen Bonds (HBs) as a standard ligand with GSK-3. Compound 4h was the most active compound against rotavirus Wa, HAVHM175, and HSV strains with a reduction of 30%, 40%, and 70%, respectively.Conclusion:Compound 4h was the most active compound and could act as a prospective lead molecule for anticancer agent.


1988 ◽  
Vol 53 (9) ◽  
pp. 1943-1945
Author(s):  
Pavel Hobza ◽  
Camille Sandorfy

The interaction of the 6-O methylguanine cation with cytosine and thymine was studied using the ab initio SCF method in combination with a London type expression for dispersion energy. The structure of the complex formed with cytosine differs from that found previously with guanine itself.


MRS Advances ◽  
2020 ◽  
Vol 5 (16) ◽  
pp. 815-823
Author(s):  
Ian Sands ◽  
Jinhyung Lee ◽  
Wuxia Zhang ◽  
Yupeng Chen

AbstractRNA delivery into deep tissues with dense extracellular matrix (ECM) has been challenging. For example, cartilage is a major barrier for RNA and drug delivery due to its avascular structure, low cell density and strong negative surface charge. Cartilage ECM is comprised of collagens, proteoglycans, and various other noncollagneous proteins with a spacing of 20nm. Conventional nanoparticles are usually spherical with a diameter larger than 50-60nm (after cargo loading). Therefore, they presented limited success for RNA delivery into cartilage. Here, we developed Janus base nanotubes (JBNTs, self-assembled nanotubes inspired from DNA base pairs) to assemble with small RNAs to form nano-rod delivery vehicles (termed as “Nanopieces”). Nanopieces have a diameter of ∼20nm (smallest delivery vehicles after cargo loading) and a length of ∼100nm. They present a novel breakthrough in ECM penetration due to the reduced size and adjustable characteristics to encourage ECM and intracellular penetration.


2020 ◽  
Vol 56 (2) ◽  
pp. 201-204 ◽  
Author(s):  
Kinga E. Szkaradek ◽  
Petr Stadlbauer ◽  
Jiří Šponer ◽  
Robert W. Góra ◽  
Rafał Szabla

Formation of an excited-state complex enables ultrafast photorelaxation of dark nπ* states in GC and HC base pairs.


2015 ◽  
Vol 127 (49) ◽  
pp. 14932-14935 ◽  
Author(s):  
Katharina Röttger ◽  
Hugo J. B. Marroux ◽  
Michael P. Grubb ◽  
Philip M. Coulter ◽  
Hendrik Böhnke ◽  
...  

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