title: Atomic force microscope imaging of DNA and DNA repair proteins: applications in radiobiological research.
abstract: By using the atomic force microscope (AFM), three-dimensional structures of biological specimens may be imaged at nanometer resolution. Furthermore, samples can be imaged in air or in fluid environments. The tapping mode of AFM operation for imaging has offered a significant advance in visualizing soft biological structures, such as DNA, proteins, and membranes. Here, we review the principles underlying the application of this instrument to radiation biological investigations. We focus on examples of proteins involved in the processes of repair of damaged DNA, including poly(ADP-ribose) polymerase, Ku protein, and DNA protein kinase. Novel observations on the character of DNA damage and repair have been addressed by direct visualization of DNA and protein-DNA interactions, such as the observation that the Ku protein is capable of physically joining DNA fragments in vitro. The AFM offers a powerful tool for investigating biologically important molecular interactions that are relevant to DNA damage and repair processes.
authors.affiliation: Department of Radiation Medicine, Georgetown University Medical Center, Washington, DC 20007, USA.
authors.forename: D
authors.initials: D
authors.lastname: Pang
authors.forename: B
authors.initials: B
authors.lastname: Vidic
authors.forename: J
authors.initials: J
authors.lastname: Rodgers
authors.forename: B L
authors.initials: BL
authors.lastname: Berman
authors.forename: A
authors.initials: A
authors.lastname: Dritschilo
mesh_terms: D000388:Air; D034961:Antigens, Nuclear; D001324:Autoantigens / Q000648:ultrastructure; D004247:DNA / Q000648:ultrastructure*; D004249:DNA Damage; D004265:DNA Helicases; D011088:DNA Ligases / Q000648:ultrastructure*; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000648:ultrastructure; D006801:Humans; D000072200:Ku Autoantigen; D008566:Membranes / Q000648:ultrastructure; D018625:Microscopy, Atomic Force / Q000379:methods; D008967:Molecular Biology; D009687:Nuclear Proteins / Q000648:ultrastructure; D011065:Poly(ADP-ribose) Polymerases / Q000648:ultrastructure; D011494:Protein Kinases / Q000648:ultrastructure; D011506:Proteins / Q000648:ultrastructure; D011853:Radiobiology; D014157:Transcription Factors / Q000648:ultrastructure
chemical_list: D034961:Antigens, Nuclear; D001324:Autoantigens; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D011506:Proteins; D014157:Transcription Factors; D004247:DNA; D011065:Poly(ADP-ribose) Polymerases; D011494:Protein Kinases; D004265:DNA Helicases; C106893:XRCC5 protein, human; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen; D011088:DNA Ligases