59
Chapter 3
Formation of DNA Lesions, its Prevention
and Repair
Nihar R. Jena, Neha Agnihotri and Phool C. Mishra
© Springer Science+Business Media Dordrecht 2014
L. Gorb et al. (eds.), Application of Computational Techniques in Pharmacy and Medicine,
Challenges and Advances in Computational Chemistry and Physics 17,
DOI 10.1007/978-94-017-9257-8_3
P. C. Mishra ()
Department of Physics, Banaras Hindu University, Varanasi 221 005, India
e-mail: pcmishra_in@yahoo.com
N. R. Jena
Discipline of Natural Sciences, Indian Institute of Information Technology,
Design and Manufacturing, Khamaria, Jabalpur 482005, India
e-mail: nrjena@iiitdmj.ac.in
N. Agnihotri
Department of Chemistry, University of Saskatchewan, Saskatoon S7N 5C9, Canada
e-mail: n.agnihotri6@gmail.com
Abstract The present review discusses three important aspects which are intimately related to human health at the molecular level. The first aspect is the formation of DNA lesions caused due to the reactions of DNA with certain free radicals
known as reactive oxygen species (ROS) and reactive nitrogen oxide species
(RNOS). Some of these free radicals are constantly formed in biological systems
during the metabolic activities while others can be ascribed to the exposure to radiation or pollution. These species react with DNA bases, particularly guanine, leading
to base misparing, mutation and several diseases including cancer. The mechanisms
of reactions of certain ROS and RNOS with the DNA bases, particularly guanine or
its modifications are discussed. The second aspect discussed here is the role of antioxidants some of which are present inside biological systems while others can be
taken from external sources as food supplements. Certain endogenous anti-oxidants
present in biological systems inhibit the formation of reactive free radicals while
others, particularly those taken from outside, scavenge the same through appropriate chemical reactions. The molecular mechanisms of action of several anti-oxidants are discussed. The third aspect discussed here is the working of the complex
and intelligent molecular machinery which is constantly active in biological systems and removes or repairs the damaged bases. Molecular mechanisms involved
in some of these activities are reviewed. Details of recent theoretical studies on all
the three aspects mentioned above are discussed.
Chapter 3
Formation of DNA Lesions, its Prevention
and Repair
Nihar R. Jena, Neha Agnihotri and Phool C. Mishra
© Springer Science+Business Media Dordrecht 2014
L. Gorb et al. (eds.), Application of Computational Techniques in Pharmacy and Medicine,
Challenges and Advances in Computational Chemistry and Physics 17,
DOI 10.1007/978-94-017-9257-8_3
P. C. Mishra ()
Department of Physics, Banaras Hindu University, Varanasi 221 005, India
e-mail: pcmishra_in@yahoo.com
N. R. Jena
Discipline of Natural Sciences, Indian Institute of Information Technology,
Design and Manufacturing, Khamaria, Jabalpur 482005, India
e-mail: nrjena@iiitdmj.ac.in
N. Agnihotri
Department of Chemistry, University of Saskatchewan, Saskatoon S7N 5C9, Canada
e-mail: n.agnihotri6@gmail.com
Abstract The present review discusses three important aspects which are intimately related to human health at the molecular level. The first aspect is the formation of DNA lesions caused due to the reactions of DNA with certain free radicals
known as reactive oxygen species (ROS) and reactive nitrogen oxide species
(RNOS). Some of these free radicals are constantly formed in biological systems
during the metabolic activities while others can be ascribed to the exposure to radiation or pollution. These species react with DNA bases, particularly guanine, leading
to base misparing, mutation and several diseases including cancer. The mechanisms
of reactions of certain ROS and RNOS with the DNA bases, particularly guanine or
its modifications are discussed. The second aspect discussed here is the role of antioxidants some of which are present inside biological systems while others can be
taken from external sources as food supplements. Certain endogenous anti-oxidants
present in biological systems inhibit the formation of reactive free radicals while
others, particularly those taken from outside, scavenge the same through appropriate chemical reactions. The molecular mechanisms of action of several anti-oxidants are discussed. The third aspect discussed here is the working of the complex
and intelligent molecular machinery which is constantly active in biological systems and removes or repairs the damaged bases. Molecular mechanisms involved
in some of these activities are reviewed. Details of recent theoretical studies on all
the three aspects mentioned above are discussed.