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Published on: November 12, 2017
Peroxynitrite-induced conformational changes in DNA that lead to cell death: UV, CD spectral, molecular dynamics
G Anushree1, P Aravind2, D Vinod3
1Department of Biotechnology and Microbiology, Bangalore University, Bangalore, Karnataka, India.
Abstract:
Peroxynitrite is known to react with biomolecules leading to their structural and function alteration. Structural alteration in DNA induced by peroxynitrite is not clearly known. The current study was carried out to decipher the changes induced by peroxynitrite using UV-Vis spectra, circular dichrometry, molecular dynamics simulation followed by restriction digestion. Apoptotic markers Bax, Bcl-2 and caspase genes were also studied by FACS in peroxynitrite induced PC12 cells. The results obtained showed that PXN binds to DNA leading to hyperchromicity of DNA in the presence of PXN over a period of time and the same was established by In silico studies where PXN modifies the DNA to accommodate itself into the stacking and brings about the significant structural alterations. Further, FACS studies reveal that Bcl-2 gene expression was down regulated whereas BAXand caspase genes were up regulated compared to control concluding that PXN induces apoptotic cell death in PC12 cells.
Insights
Peroxynitrite (PXN) alters DNA structure and function, leading to cell death. This study reveals PXN
Area of Science:
- Biochemistry and Molecular Biology
- Cellular and Molecular Toxicology
Background:
- Peroxynitrite (PXN) is a reactive nitrogen species known to modify biomolecules.
- The specific structural alterations induced by PXN in DNA remain incompletely understood.
Purpose of the Study:
- To investigate the structural and functional changes in DNA caused by peroxynitrite.
- To elucidate the role of peroxynitrite in inducing apoptosis in PC12 cells.
Main Methods:
- UV-Vis spectroscopy and circular dichroism to analyze DNA structure.
- Molecular dynamics simulations and restriction digestion for detailed structural analysis.
- Flow-activated cell sorting (FACS) to study apoptotic markers (Bax, Bcl-2, caspase).
Main Results:
- Peroxynitrite binding to DNA caused hyperchromicity, indicating structural changes.
- In silico studies confirmed DNA modification by peroxynitrite to accommodate its structure.
- FACS analysis showed down-regulation of Bcl-2 and up-regulation of Bax and caspase genes.
Conclusions:
- Peroxynitrite induces significant structural alterations in DNA.
- Peroxynitrite triggers apoptotic cell death in PC12 cells via modulation of key apoptotic genes.
