Changes of hydration during conformational transitions of DNA.
Fiber X-ray diffraction and measurement of fiber dimensions yields information about the hydration of DNA in fibers. The results obtained give us the fraction of nucleotides in the B form for the A-B transition or the rate of progression for the B-C transition as functions of the number of water molecules per nucleotide. The present experimental results confirm the importance of cooperativity in the A-B transition and the progressive change of the DNA double helix conformation during the C-B transition. At least twenty additional water molecules per nucleotide are necessary to stabilize the B form for DNA molecules in fibers following the A to B transition whereas only ten are sufficient when the B conformation is obtained starting from the C form.
Harmouchi
M
M
Laboratoire de Biophysique Moléculaire, UA CNRS 494, Faculté des Sciences, Université de Nancy I, France.
Albiser
G
G
Premilat
S
S
D004247:DNA / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
D014867:Water; D004247:DNA