TY - JOUR
T1 - Interaction of the Alternating Double Stranded Copolymer poly(dA-dT)·poly(dA-dT) with NiCl2 and CdCl2: Solution Behavior
AU - Gennaro, Giuseppe
AU - Giuliani Ricci, Anna Maria
AU - Airoldi, Marta
AU - Giomini, Marcello
AU - Giustini, Mauro
PY - 2007
Y1 - 2007
N2 - The thermal denaturation of the synthetic high molecular weight double stranded polynucleotide poly(dA-dT)·poly(dA-dT) has been studied in aqueous buffered solution (Tris 1.0mM; pH 7.8±0.2) in the presence of increasing concentrations of either Ni2+ (borderline cation) or Cd2+ (soft cation) at four different constant ionic strength values (NaCl), making use of UV and circular dichroism (CD) spectroscopies. The experimental results show that the B-type double helix of the polymer is stabilized against thermal denaturation in the presence of both cations at low concentrations, relative to the systems where only NaCl is present, in the same conditions of ionic strength and pH. The effect is more pronounced for Ni2+ than for Cd2+. At higher concentrations, both cations start to destabilize the double helix, with Cd cations inducing larger variations of Tm. In many cases, when denaturation starts, interstrand cross-linking occurs with formation of aggregates that precipitate.
AB - The thermal denaturation of the synthetic high molecular weight double stranded polynucleotide poly(dA-dT)·poly(dA-dT) has been studied in aqueous buffered solution (Tris 1.0mM; pH 7.8±0.2) in the presence of increasing concentrations of either Ni2+ (borderline cation) or Cd2+ (soft cation) at four different constant ionic strength values (NaCl), making use of UV and circular dichroism (CD) spectroscopies. The experimental results show that the B-type double helix of the polymer is stabilized against thermal denaturation in the presence of both cations at low concentrations, relative to the systems where only NaCl is present, in the same conditions of ionic strength and pH. The effect is more pronounced for Ni2+ than for Cd2+. At higher concentrations, both cations start to destabilize the double helix, with Cd cations inducing larger variations of Tm. In many cases, when denaturation starts, interstrand cross-linking occurs with formation of aggregates that precipitate.
KW - Circular Dichroism
KW - Model polynucleotides
KW - Nickel (II) and Cadmium (II) ions
KW - Thermal denaturation
KW - UV-spectroscopy
KW - Circular Dichroism
KW - Model polynucleotides
KW - Nickel (II) and Cadmium (II) ions
KW - Thermal denaturation
KW - UV-spectroscopy
UR - http://hdl.handle.net/10447/11496
M3 - Article
VL - 25
SP - 77
EP - 84
JO - JOURNAL OF BIOMOLECULAR STRUCTURE & DYNAMICS
JF - JOURNAL OF BIOMOLECULAR STRUCTURE & DYNAMICS
SN - 0739-1102
ER -