Strain dependent UV degradation of Escherichia coli DNA monitored by Fourier transform infrared spectroscopy

• Structural characteristics of DNAs from nonpathogenic Escherichia coli strains are discussed.
• Structural characteristics of UV irradiated DNA from E. coli strains are given.
• Strain dependent UV damage of E. coli DNA with irradiation time has been observed.
• Upon UV irradiation alterations in nucleic acid bases, base pairing and base stacking have been found.
• Changes in nucleic acid conformation and in a lesser extent, in deoxyribose were detected in UV irradiated DNAs.

In this work we present a method for detection of DNA isolated from nonpathogenic Escherichia coli strains, respectively. Untreated and UV irradiated bacterial DNAs were analyzed by FT-IR spectroscopy, to investigate their screening characteristic features and their structural radiotolerance at 253.7 nm.FT-IR spectra, providing a high molecular structural information, have been analyzed in the wavenumber range 800–1800 cm−1. FT-IR signatures, spectroscopic band assignments and structural interpretations of these DNAs are reported.Also, UV damage at the DNA molecular level is of interest. Strain dependent UV degradation of DNA from E. coli has been observed. Particularly, alterations in nucleic acid bases, base pairing and base stacking have been found. Also changes in the DNA conformation and deoxyribose were detected.Based on this work, specific E. coli DNA-ligand interactions, drug development and vaccine design for a better understanding of the infection mechanism caused by an interference between pathogenic and nonpathogenic bacteria and for a better control of disease, respectively, might be further investigated using Fourier transform infrared spectroscopy. Besides, understanding the pathways for UV damaged DNA response, like nucleic acids repair mechanisms is appreciated.

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