Nucleos(t)ide analogues (NAs) are effective therapeutic agents for the treatment of chronic hepatitis B virus (HBV) infection. However, longterm use of NAs is often hampered by the emergence of drug resistance mutations, causing potentially serious consequences such as liver decompensation and mortality. A more sensitive method for early detection of drug resistance mutations is needed. Convent...

In this study we heated insoluble residues, obtained after Triton-X-100 (0.1 v/v%) extraction of erythrocyte ghost membranes (EGMs). Specific heat capacity, electric capacitance and resistance, and optical transmittance (280 nm) sustained sharp changes at 49°C (TA) and 66°C (TC), the known denaturation temperatures of spectrin and band 3, respectively. The change at TA was selectively inhibited...

The simian virus 40 (SV40) large tumor antigen(T antigen) has been shown to induce the melting of 8 bp within the SV40 origin of replication. We found previously that a 'pseudo-origin' DNA molecule (PO-8) containing a central 8 nt single-stranded DNA (ssDNA) bubble was efficiently bound and denatured by human replication protein A (hRPA). To understand the mechanism by which hRPA denatures thes...

Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy using a special waveguide based on a silver halide fiber was used for probing the heat-induced secondary structure and conformation changes of bovine serum albumin (BSA). From the secondary derivative and the curve fitting of the obtained ATR-FTIR spectra, the changes of the BSA secondary structure with temperature w...

The reversible denaturation of Escherichia coli alkaline phosphatase (AP) was followed by monitoring changes in enzymatic activity as well as by measurements of the time-resolved room temperature phosphorescence from Trp 109. It is well known that the denaturants, ethylene diamine tetraacetic acid (EDTA), acid and guanidine hydrochloride (GdnHCl) inactive AP by different mechanisms as reflected...

The thermal denaturation of the dimeric enzyme triosephosphate isomerase (TIM) from Saccharomyces cerevisiae was studied by spectroscopic and calorimetric methods. At low protein concentration the structural transition proved to be reversible in thermal scannings conducted at a rate greater than 1.0 degrees C min(-1). Under these conditions, however, the denaturation-renaturation cycle exhibite...

Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used to monitor changes in the secondary structure and thermal stability of beta-lactoglobulin A and B in the presence of sodium dodecyl sulphate (SDS), N-ethylmaleimide (NEM), urea and cysteine. An increase in the thermal stabilities of both proteins was noted in the presence of 10 mM-SDS. In the pr...

The kinetics of thermal denaturation of ceruloplasmin in water and in water with different percentage of D2O in the temperature range 25-85 degrees C, following the optical density change of the 610 nm charge transfer band of the protein has been investigated. A temperature Tt approximately equal to 65 degrees C above which an irreversible denaturation process of the protein active site takes p...

It is shown that microwave irradiation can affect the kinetics of the folding process of some globular proteins, especially beta-lactoglobulin. At low temperature the folding from the cold denatured phase of the protein is enhanced, while at a higher temperature the denaturation of the protein from its folded state is enhanced. In the latter case, a negative temperature gradient is needed for t...

In this Letter, we report direct measurement of large low frequency temperature fluctuations in double stranded DNA when it undergoes a denaturation transition. The fluctuation, which occurs only in the temperature range where the denaturation occurs, is several orders more than the expected equilibrium fluctuation. It is absent in single stranded DNA of the same sequence. The fluctuation at a ...