acoustical investigation of poly(da) poly(dt), poly[d(a-t)]poly[d(a-t)i, poly(a) poly(u) and DNA hydration in dilute aqueous solutions
Buckin V.A., Kankiya B.I., Sarvazyan A.P. and Uedaira H.
Nucleic Acids Research, 17, pp. 4189-4203 (1989)
Apparent molar adiabatic compressibilities and apparent molar volumes of poly[d(AT)] poly[d(A—T)], poly(dA) poly(dT), DNA and poly(A)·poly(U) in aqueous solutions were determined at 10ºC. The change of concentration increment of the ultrasonic velocity upon replacing counter ion Cs+ by the Mg2+ ion was also determined for these polymers. The following conclusions have been made: (1) the hydration of the double helix of poly(dA)·poly(dT) is remarkably larger than that of other polynucleotides; (2) the hydration of the AT pair in the B—form DNA is larger than that of the GC pair; (3) the substitution of Cs+ for Mg2+ ions as counter ions results in a decrease of hydration of the system polynucleotide plus Mg2+ and (4) the magnitude of this dehydration depends on the nucleotide sequence; the following rule is true: the lesser is a polynucleotide hydration, the larger dehydration upon chaning Cs+ for Mg2+ ions in the ionic atmosphere of polynucleotide.