Electrochemical and spectrometric studies of double-strand calf thymus gland DNA denatured by Al(III) at neutral pH.
The interaction between double-strand calf thymus gland DNA (ds-DNA) and Al(III) was studied by using differential pulse voltammetry (DPV) at a hanging mercury drop electrode (HMDE), Raman spectrometry and circular dichroism (CD) spectra. It was shown that at neutral pH ds-DNA did not produce any cathodic peak at the HMDE in the potential window from -550 to -2000 mV vs. SCE. However, in the presence of Al(III), a cathodic peak was generated at about -1660 mV, which is ascribed to a reduction of adenine and cytosine residues of single denatured DNA (sd-DNA). It was concluded that ds-DNA was completely denatured to sd-DNA by Al(III) at a neutral pH. The apparent denaturing kinetic velocity constants of ds-DNA by Al(III) were derived from linear increases of the cathodic peak currents with time. When [Al(III)]x[OH(-)](3) > or = 2 x 10(-26), the precipitation of Al(OH)(3) was observed and identified by the Raman spectrum, and inductively coupled plasma atomic emission spectrometry (ICP-AES). CD spectra showed that the B-type of structure conformations of ds-DNA and related sd-DNA did not change with the increment of Al(III) from 5.0 x 10(-7) to 1.0 x 10(-5) M, but the corresponding absorption strengths increased. The related physiological significances and possible applications of the observations were considered.
Zhang
Fuping
F
School of Chemistry & Chemical Engineering, State Key Laboratory of Coordination Chemistry of China, Nanjing University, China.
Cao
Qing
Q
Cheng
Jiongjia
J
Zhang
Caihua
C
An
Na
N
Bi
Shuping
S
D000535:Aluminum / Q000737:chemistry*; D000818:Animals; D002417:Cattle; D004247:DNA / Q000737:chemistry*; D004563:Electrochemistry; D006863:Hydrogen-Ion Concentration; D008628:Mercury / Q000737:chemistry; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D013950:Thymus Gland / Q000378:metabolism
D004247:DNA; D000535:Aluminum; D008628:Mercury