A series of 9-(pyridin-2'-yl)-aminoacridines was prepared and analyzed for their ability to change the thermal denaturation temperature of genomic calf thymus DNA. Development of a QSAR equation indicated that electron withdrawing groups on the pyridine ring promoted the interaction with double stranded DNA.

Thermal denaturation of protonated polynucleotides is accompanied by a change in protonation [l-5] . The thermal transition at a given pH can thus be directly related to the pk’ of the proton-induced structural transition at a given temperature. For poly (A’).poly (A+) a strict relationship has been shown to hold over a large range of conditions [4-61. In fig. 1 the results in the literature an...

The velocity of enzyme catalysed reactions increases with temperature to a maximum beyond which enzyme activity decreases because of protein denaturation. Many biological reactions have a 10 °C temperature coefficient (Qi0) of 2; that is, their rate of reaction doubles for a 10 °C temperature increase [62]. In mammals, protein denaturation begins at about 42 °C and internal temperatures at or a...

We describe a simple microfluidic device for the rapid analysis of protein thermal stability using a novel imaging method. The change in UV absorption upon thermal denaturation or aggregation of proteins is used to get a spatial image of proteins' folding or aggregation state along a linear temperature gradient.

Significant non-reversible two-state denaturation was observed for proteins such as myoglobin (Mb) and α-chymotrypsin (CT) with decreasing temperature in the presence of 1-butyl-3-methylimidazolium-based ([C4mim](+)X(-)) ionic liquids (ILs) with various anions (X(-)). Interestingly, for the first time, ILs having acetate and bromide anions were proven to counteract the cold-induced unfolding of...

The 1.7A resolution crystal structure of recombinant family G/11 beta-1,4-xylanase (rXynA) from Bacillus subtilis 1A1 shows a jellyroll fold in which two curved beta-sheets form the active-site and substrate-binding cleft. The onset of thermal denaturation of rXynA occurs at 328 K, in excellent agreement with the optimum catalytic temperature. Molecular dynamics simulations at temperatures of 2...

We have performed molecular dynamics simulation on B-DNA duplex (CGCGAATTGCGC) at different temperatures. The DNA was immerged in a salt-water medium with 1 M NaCl concentration to investigate salt effect on the denaturation process. At each temperature, configurational entropy is estimated using the covariance matrix of atom-positional fluctuations, from which the melting temperature (T(m)) wa...

In this study at first , an azo dye, 2,7- naphthalenediol, 2-[(4-Bromophenyl)azo (BPAND) as a ligand has been synthesized by addition of p-Bromoaniline to the modified montomorillonite K10 clay. This ligand was characterized using 1H-NMR, UV-Vis and IR spectroscopies. Subsequently, its interaction with calf thymus deoxyribonucleicacid ,ct-DNA was investigated in 5 mM phosphate buffer solution, ...

The results of a thermodynamic calculation of the excess heat capacity that is based on experimental observations and that incorporates the effects of ligand binding on the two-state, thermal denaturation of a protein are presented. For a protein with a single-binding site on the native species and at subsaturating concentrations of ligand, bimodal or unimodal thermograms were computed merely b...

The conformational stabilities of eight proteins in terms of the free energy differences between the native "folded" state of the protein and its "unfolded" state were determined at 298 K by two methods: chemical denaturation at 298 K and extrapolation to 298 K of the thermal denaturation results at high temperature. The proteins were expressed in Escherichia coli from the Haemophilus influenza...