The thermodynamical properties of heterogeneous DNA sequences are computed by path-integral techniques applied to a nonlinear model Hamiltonian. The base pairs relative displacements are interpreted as time-dependent paths whose amplitudes are consistent with the model potential for the hydrogen bonds between complementary strands. The portion of configuration space contributing to the partitio...

We investigate the thermal denaturation of DNA hairpins using molecular dynamics simulations of a simple model describing the molecule at a scale of a nucleotide. The model allows us to analyze the different interacting features that determine how an hairpin opens, such as therole of the loop and the properties intrinsic to the stem.

In the last two decades, single-molecule force measurements using optical and magnetic tweezers and atomic force spectroscopy have dramatically expanded our knowledge of nucleic acids and proteins. These techniques characterize the force on a biomolecule required to produce a given molecular extension. When stretching long DNA molecules, the observed force-extension relationship exhibits a char...

Alkali denaturation of the haemoglobin derived from burned patients at various intervals from the time of the injury was investigated. A delayed denaturation curve was always found. The involvement of the transfused cells was established by a differential agglutination technique. Red cell populations were fractionated into two portions, one of which was probably enriched in younger cells. This ...

The denaturation of dimeric creatine kinase (CK) induced by urea and guanidine hydrochloride (GuHCl) has been studied by small angle X-ray scattering (SAXS), which is a direct way to measure the changes in the overall dimensions of a protein molecule. The radii of gyration (Rg) of CK are 29+/-0.4 angstroms in the native state and 46+/-1.5 angstroms in the unfolded state in either 8 M urea or 3 ...

The thermal denaturation of lysozyme in aqueous alcohol solutions has been investigated through ultraviolet difference spectrophotometry and optical rotation measurements. Alcohols used were CH30H, C2H50H, and C3H70H; concentrations up to 50% (v/v) of alcohol in water were employed. It was found that upon increasing the size or the concentration of the aliphatic alcohol, the denaturation temper...

embedding a fast-response microthermocouple inside a PCR reaction tube, we were able to study the thermodynamic process from the block via the tube to the PCR sample in more detail. This physical evaluation allowed us to distinguish accurate performers (category 1 and 2 cyclers) from less accurate performers (category 3 cyclers). At the denaturation step, during the first 15 s the thermal inhom...

The denaturation of ribonuclease A by guanidine hydrochloride, lithium bromide, and lithium chloride and by mixed denaturants consisting of guanidine hydrochloride and one of the denaturants lithium chloride, lithium bromide, and sodium bromide was followed by difference spectral measurements at pH 4.8 and 25 degrees C. Both components of mixed denaturant systems enhance each other's effect in ...

The denaturation of protein by pressure has been generally well known since the findings of the perfect coagulation of egg white by a pressure of 7,000 atm within 30 min by Bridgman (J Biol Chem 19:511-512, 1914), and Kiyama and Yanagimoto (Rev Phys Chem Jpn 21:41-43, 1951) confirmed that the coagulation occurs above 3,880 kg cm(-2). Grant et al. (Science 94:616, 1941) and Suzuki and Kitamura (...

Objective: The objective of this study was to determine the changes in myoglobin denaturation through cooking three different muscles medium rare, medium, or well-done degrees doneness.