title: The unusual conformation adopted by the adenine tracts in kinetoplast DNA.
abstract: To determine the structural features responsible for the curvature of kinetoplast DNA, we studied 13 adenine tracts in Crithidia fasciculata kinetoplast DNA. The structures of the A tracts were analyzed by cutting the DNA with hydroxyl radical. Reactivity of hydroxyl radical toward the DNA backbone progressively decreased in the 5'----3' direction of each A tract. The cutting pattern of the T-rich strand was offset by 1 or 2 bp from the pattern on the A-rich strand. An A tract in a restriction fragment from plasmid pBR322 had the same cutting pattern as the kinetoplast A tracts. We interpret these experiments to show that in A tracts the width of the minor groove decreases smoothly from the 5'----3' end of the A tract.
mesh_terms: D000225:Adenine; D000818:Animals; D001483:Base Sequence; D003421:Crithidia / Q000235:genetics; D004270:DNA, Circular / Q000302:isolation & purification; D018105:DNA, Kinetoplast; D006878:Hydroxides; D017665:Hydroxyl Radical; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D013816:Thermodynamics
chemical_list: D004270:DNA, Circular; D018105:DNA, Kinetoplast; D006878:Hydroxides; D017665:Hydroxyl Radical; D000225:Adenine