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V Dötsch

Publications and source records attributed to V Dötsch.

25 records · Page 2Linked to original sources
PubMed1996

The role of protein-solvent interactions in protein unfolding.

Protein unfolding occurs when the balance of forces between the protein's interaction with itself and the protein's interaction with its environment is disrupted. The disruption of this balance of forces may be as simple as a perturbance of the normal water structure around the protein. A decrease in the normal water-water interaction will result in an increase in the relative interaction of water with the protein. An increase in the number of interactions between water and the protein may initiate a protein's unfolding. This model for protein unfolding is supported by a range of recent experimental and computational data.

Computer Simulation↗
PubMed1995

Exploring the role of the solvent in the denaturation of a protein: a molecular dynamics study of the DNA binding domain of the 434 repressor.

Molecular dynamics simulations of the DNA binding domain of 434 repressor are presented which aim at unraveling the role of solvent in protein denaturation. Four altered solvent models, each mimicking various possible aspects of the addition of a denaturant to the aqueous solvent, were used in the simulations to analyze their effects on the stability of the protein. The solvent was altered by selectively changing the Coulombic interaction between water and protein atoms and between different water molecules. The use of a modified solvent model has the advantage of mimicking the presence of denaturant without having denaturant molecules present in the simulation, which would require much longer simulations. In these simulations, only an increase in the solvent-protein Coulombic interaction causes initiation of protein unfolding in a manner consistent with NMR data. The altered solvent thus provides a model of a denaturing environment for studying protein unfolding.

Amino Acid Sequence↗
PubMed1995

Salt-stabilized globular protein structure in 7 M aqueous urea solution.

A 7 M aqueous urea solution of the 63-residue N-terminal domain of the 434-repressor at pH 7.5 and 18 degrees C contains a mixture of about 10% native, folded protein and 90% unfolded protein. Interconversion between the two conformations is slow on the NMR chemical shift time scale, so that observation of separate resonances can be used to monitor the equilibrium between folded and unfolded protein when changing the solution conditions. In this paper we describe the influence of various salts or non-ionic compounds on this conformational equilibrium. Solution conditions are described which contain a homogenous preparation of the folded protein in the presence of 6 to 7 M urea, providing a basis for an NMR structure determination in concentrated urea and for studies of the solvation of the folded protein in mixed water/urea/salt environments.

Bacteriophages↗
PubMed1995

Interaction of urea with an unfolded protein. The DNA-binding domain of the 434-repressor.

Experimental techniques are presented for the observation of the solvation of the unfolded form of a globular protein, the N-terminal 63-residue polypeptide from the 434 repressor, in 7 M aqueous urea solution by both water and urea. With the use of 15N-labelled urea it is demonstrated that the cross sections through two-dimensional nuclear Overhauser enhancement (NOE) spectra at the chemical shifts of H2O and urea both contain direct NOEs with the protein, under conditions where exchange peaks are observed only in the water cross section. A preliminary analysis of the data showed that the residence times of urea molecules in solvation sites near the methyl groups of Val, Leu and Ile are significantly longer than those of water molecules in the same sites.

Amino Acids↗