An all atom molecular dynamics simulation was used to explore the atomic detail mechanism of guanidinium induced unfolding of the protein ubiquitin. Ubiquitin unfolds through pre-unfolded (intermediate) states, i.e. guanidinium induced unfolding of ubiquitin appears to be a multi-step process, and loss of hydrophobic contacts of C-terminal residues is crucial for ubiquitin unfolding. Free-energ...

Cervical mucins and fragments thereof were studied by sedimentation-velocity, rotatory viscometry and laser light-scattering performed as photon-correlation spectroscopy as well as low-angle total-intensity measurements. The Mr of the whole mucins is 10 X 10(6)-15 X 10(6), whereas fragments obtained after reduction of disulphide bonds ('subunits') have Mr 2.1 X 10(6)-2.9 X 10(6), depending on t...

The residue asparagine-52 of rat cytochrome c and baker's yeast iso-1-cytochrome c was mutated to isoleucine by site-directed mutagenesis, and the unfolding of the wild-type and mutant proteins in urea or guanidinium chloride solutions was studied. Whereas the yeast mutant cytochrome unfolded in 4-7 M urea with a rate constant (k) of 1.7 x 10(-2) s-1, the rat mutant protein unfolded with k = 5....

The discovery of several new unusually stable aggregates of arginine that are intermolecularly bound by salt bridges is reported. Quadrupole ion-trap mass spectrometry provides evidence for the stability of arginine in the zwitterionic state, where the protonated guanidinium group of one arginine interacts strongly with the carboxylate of another to form stable noncovalent complexes, coordinate...

The dissociation and unfolding of the homodimeric glutathione transferase (GST) Pi from human placenta, using different physicochemical denaturants, have been investigated at equilibrium. The protein transitions were followed by monitoring loss of activity, intrinsic fluorescence, tyrosine exposure, far-u.v. c.d. and gel-filtration retention time of the protein. At low denaturant concentration ...

This paper describes data related to the research article "Testing the dependence of stabilizing effect of osmolytes on the fractional increase in the accessible surface area on thermal and chemical denaturations of proteins" [1]. Heat- and guanidinium chloride (GdmCl)-induced denaturation of three disulfide free proteins (bovine cytochrome c (b-cyt-c), myoglobin (Mb) and barstar) in the presen...

Inactivation of pancreatic RNAase A occurs in guanidinium chloride (GdmCl) at low concentrations before the unfolding of the molecule as a whole can be detected [Liu and Tsou (1987) Biochim. Biophys. Acta 916, 455-464]. We have now shown that the rate of digestion of the RNAase molecule by either trypsin or proteinase K increases significantly at low concentrations of GdmCl where the enzyme is ...

Proteoglycans extracted from separated specimens of healthy human gingival epithelium and from connective tissue have been purified. The epithelial proteoglycans fractionated as a single included peak on Sepharose 4B-CL and contained heparan sulphate and dermatan sulphate glycosaminoglycans. The connective-tissue proteoglycans separated into three major populations on Sepharose 4B-CL, one of wh...

The serine proteinase isolated from Thermomonospora fusca YX shows considerable thermal stability up to 80 °C, and progressive inactivation occurs at higher temperatures. Lyotropic salts affected the thermal stability of the enzyme at 85 °C, suggesting that disruption of hydrophobic interactions play an important role in the decreased thermal stability of the enzyme above 80 'C. Thermal stabili...

Synthetic receptors for phosphates and phosphonates have been generated in SiO2 xerogels via a surface molecular imprinting method. The monomer 3-trimethoxy silylpropyl-1-guanidinium chloride (1) was developed to prepare receptor sites capable of binding with substrates through a combination of ionic and hydrogen bond interactions. HPLC studies and adsorption isotherms performed in water have f...