title: Processing of abasic site damaged lesions by APE1 enzyme on DNA adsorbed over normal and organomodified clay.
abstract: The efficiency of the apurinic/apyrimidinic endonuclease (APE1) DNA repair enzyme in the processing of abasic site DNA damage lesions at precise location in DNA oligomer duplexes that are adsorbed on clay surfaces was evaluated. Three different forms of clay namely montmorillonite, quaternary ammonium salt modified montmorillonite and its boiled counterpart i.e. partially devoid of organic moiety were used for a comparative study of adsorption, desorption and DNA repair efficiency on their surfaces. The interaction between the DNA and the clay was analysed by X-ray diffraction, Atomic force microscopy, UV-Vis spectroscopy and Infrared spectroscopy. The abasic site cleavage efficiency of APE1 enzyme was quantitatively evaluated by polyacrylamide gel electrophoresis. Apart from the difference in the DNA adsorption or desorption capacity of the various forms of clay, substantial variation in the repair efficiency of abasic sites initiated by the APE1 enzyme on the clay surfaces was observed. The incision efficiency of APE1 enzyme at abasic sites was found to be greatly diminished, when the DNA was adsorbed over organomodified montmorillonite. The reduced repair activity indicates an important role of the pendant surfactant groups on the clay surfaces in directing APE1 mediated cleavage of abasic site DNA damage lesions.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Patna, Patna 800013, Bihar, India.
authors.forename: Bhavini
authors.initials: B
authors.lastname: Kumari
authors.affiliation: Department of Materials Science and Engineering, Indian Institute of Technology Patna, Patna 800013, Bihar, India.
authors.forename: Shib Shankar
authors.initials: SS
authors.lastname: Banerjee
authors.affiliation: Department of Chemistry, Indian Institute of Technology Patna, Patna 800013, Bihar, India.
authors.forename: Vandana
authors.initials: V
authors.lastname: Singh
authors.affiliation: Department of Chemistry, Indian Institute of Technology Patna, Patna 800013, Bihar, India. Electronic address: prolay@iitp.ac.in.
authors.forename: Prolay
authors.initials: P
authors.lastname: Das
authors.affiliation: Department of Materials Science and Engineering, Indian Institute of Technology Patna, Patna 800013, Bihar, India.
authors.forename: Anil K
authors.initials: AK
authors.lastname: Bhowmick
mesh_terms: D000327:Adsorption; D001546:Bentonite / Q000737:chemistry* / Q000633:toxicity; D004247:DNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D053837:DNA Cleavage; D004249:DNA Damage; D004260:DNA Repair; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000378:metabolism*; D008958:Models, Molecular; D016296:Mutagenesis; D009690:Nucleic Acid Conformation; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D000644:Quaternary Ammonium Compounds; D001546:Bentonite; D004247:DNA; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase
keywords: APE1; Abasic site; DNA damage; Montmorillonite; Organomodified montmorillonite