In this article, we report on the electronic monitoring of DNA denaturation by NaOH using electrochemical impedance spectroscopy in combination with fluorescence imaging as a reference technique. The probe DNA consisting of a 36-mer fragment was covalently immobilized on nanocrystalline-diamond electrodes and hybridized with different types of 29-mer target DNA (complementary, single-nucleotide...

Globular proteins undergo structural transitions to denatured states when sufficient thermodynamic state or chemical perturbations are introduced to their native environment. Cold denaturation is a somewhat counterintuitive phenomenon whereby proteins lose their compact folded structure as a result of a temperature drop. The currently accepted explanation for cold denaturation is based on an as...

Sso7d from the thermoacidophilic archaebacterium Sulfolobus solfataricus is a small globular protein with a known three-dimensional structure. Inspection of the structure reveals that Phe31 is a member of the aromatic cluster forming the protein hydrophobic core, whereas Trp23 is located on the protein surface and its side chain exposed to the solvent. The thermodynamic consequences of the subs...

Temperature is probably the most important environmental factor infl uencing the performance of species, especially in ectotherms, the majority of species on Earth. Thermal performance curves are typically asymmetrically bell-shaped, with a progressive increase in fi tness from the lowest limit of temperature tolerance to an optimum, after which a sharp decline occurs (Fig. 1A). Denaturation of...

A method is suggested to determine valid and authentic values of thermodynamic stability parameters of proteins from their heat-induced conformational transition curves. We show (a) that the estimate of ∆Hm, the enthalpy change on denaturation at Tm, the midpoint of denaturation, is significantly less than ∆Hm, the value obtained by the calorimetric measurements, if the analysis of the conforma...

Tetratricopeptide repeat (TPR) is a structural motif mediating variety of protein-protein interactions. It has a high potential to serve as a small, stable and robust, non-immunoglobulin ligand binding scaffold. In this study, we showed the consensus approach to design the novel protein called designed tetratricopeptide repeat (dTPR), composed of three repeated 34 amino-acid tetratricopeptide m...

Laser-induced thermotherapy (LITT) is an established minimally invasive percutaneous technique of tumor ablation. Nevertheless, there is a need to predict the effect of laser applications and optimizing irradiation planning in LITT. Optical attributes (absorption, scattering) change due to thermal denaturation. The work presents the possibility to identify these temperature dependent parameters...

Fibroblasts from many patients with osteogenesis imperfecta (OI) synthesize and secrete Type I collagen which is both overmodified and exhibits a decreased thermal denaturation temperature. We have examined the relationship between overmodification and decreased melting temperature in several favorable OI mutants by selectively inhibiting lysyl hydroxylase activity with the drug Minoxidil and c...

A specific method is described for selecting thermosensitive mutants of Escherichia coli K-12 able to grow on 2-keto-3-deoxy-D-gluconate (KDG) and D-glucuronate at 2, but not at 42 degrees C. The extensive analysis of one such mutant is consistent with the conclusion that the carrier molecule responsible for KDG and glucuronate uptake becomes thermolabile. (i) Growth on a variety of carbon sour...

Published data relating the concentration of 4-hydroxyproline residues to the stability of collagen was used to estimate the different effects of two types of triplets: (Gly-X-Hyp) and (Gly-Pro-Hyp). The data comprised mainly fibril-forming collagens, which exhibit highly cooperative helix-coil transitions at temperatures that are remarkably close to body temperature. A wide range of denaturati...