title: Applications for atomic force microscopy of DNA.
abstract: Tapping mode atomic force microscopy (AFM) of DNA in propanol, dry helium, and aqueous buffer each have specific applications. Resolution is best in propanol, which precipitates and immobilizes the DNA and provides a fluid imaging environment where adhesive forces are minimized. Resolution on exceptional images of DNA appears to be approximately 2 nm, sufficient to see helix turns in detail, but the smallest substructures typically seen on DNA in propanol are approximately 6-10 nm in size. Tapping AFM in dry helium provides a convenient way of imaging such things as conformations of DNA molecules and positions of proteins on DNA. Images of single-stranded DNA and RecA-DNA complexes are presented. In aqueous buffer DNA molecules as small as 300 bp have been imaged even when in motion. Images are presented of the changes in shape and position of circular plasmid DNA molecules.
authors.affiliation: Department of Physics, University of California, Santa Barbara 93106, USA.
authors.forename: H G
authors.initials: HG
authors.lastname: Hansma
authors.forename: D E
authors.initials: DE
authors.lastname: Laney
authors.forename: M
authors.initials: M
authors.lastname: Bezanilla
authors.forename: R L
authors.initials: RL
authors.lastname: Sinsheimer
authors.forename: P K
authors.initials: PK
authors.lastname: Hansma
mesh_terms: D010582:Bacteriophage lambda; D004247:DNA / Q000378:metabolism / Q000648:ultrastructure*; D004277:DNA, Single-Stranded / Q000648:ultrastructure; D004279:DNA, Viral / Q000648:ultrastructure; D015247:Deoxyribonuclease HindIII; D018625:Microscopy, Atomic Force / Q000379:methods*; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000648:ultrastructure; D011485:Protein Binding; D011938:Rec A Recombinases / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D004277:DNA, Single-Stranded; D004279:DNA, Viral; D004247:DNA; D011938:Rec A Recombinases; D015247:Deoxyribonuclease HindIII