Influence of a mechanical tension on the B-A and B-C conformational transitions in DNA fibres.
In the present fibre X-ray study we attempt to quantify the effect of a mechanical tension on the conformations, and transitions between the structural forms of DNA. A simple experimental device has been realized in order to apply precise mechanical forces on DNA fibres during X-ray exposure. It is shown that, as the applied tension is increased, the B----A transition can be prevented as well as with a decrease of the sodium salt content. A kind of distorted B form is then observed the helical parameters of which change with the relative humidity. On the contrary, the mechanical tension does not prevent the B----C transition; it only slows down the form change and improves the X-ray patterns up to a relative humidity of 0%.
Albiser
G
G
Laboratoire de Biophysique Moléculaire, U.A. C.N.R.S., Faculté des Sciences, Université de Nancy, France.
Harmouchi
M
M
Premilat
S
S
D000818:Animals; D002417:Cattle; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004247:DNA; D006813:Humidity; D009690:Nucleic Acid Conformation; D012965:Sodium Chloride; D012996:Solutions; D014961:X-Ray Diffraction
D012996:Solutions; D012965:Sodium Chloride; D004247:DNA