[Modeling of peptides and proteins in a membrane environment.II. Structural and energetic aspects of Glycophorin A in a lipid bilayer].

The conformational space of a hydrophobic peptide fragment of glycophorin A in a lipid membrane was studied with the Monte Carlo method using the solvation model described in the first communication of this series. The simulation was performed for various starting orientations of the peptide relative to the membrane bilayer: outside, inside, partially immersed, and transbilayer. We showed that the membrane substantially stabilizes the alpha-helical conformation of the central hydrophobic part of the glycophorin A molecule, which for the most part is immersed in the apolar core of the bilayer.

[Modeling of peptides and proteins in membrane environment. I. A solvation model mimicking a lipid bilayer].

A theoretical solvation model of peptides and proteins that mimics the heterogeneous membrane-water system was proposed. Our approach is based on the combined use of atomic parameters of solvation for water and hydrocarbons, which approximates the hydrated polar groups and acyl chains of lipids, respectively. This model was tested in simulations of several peptides: a nonpolar 20-mer polyleucine, a hydrophobic peptide with terminal polar groups, and a strongly amphiphilic peptide.

[Secondary structure of binase in solution by 1H NMR].

Nearly all resonances were assigned in the two-dimensional 1H NMR spectra of binase, guanylospecific ribonuclease from Bacillus intermedius containing 109 amino acid residues. The exchange rates of amide protons with the solvent deuterium were measured in 2H2O at pH 6.7 and 30 degrees C.

[Structure-activity study of the basic toxic component of venom from the ant Ectatomma tuberculatum].

A toxic principle of the Ectatomma tuberculatum ant venom called ectatomin was isolated. Ectatomin is a protein with molecular weight 7928 Da. Its complete amino acid sequence and spatial structure in aqueous solution were determined by protein chemistry methods and NMR spectroscopy techniques.

[Conformation of fragment 66-72 of interleukin-2 complexed with a monoclonal antibody to interleukin-2].

1H-NMR spectra of the interleukin-2 synthetic fragment Ac-Leu66-Glu-Glu-Val-Leu-Asn-Leu72-OCH3 in the presence or absence of the monoclonal antibody were analysed. The data obtained are consistent with an extended unordered conformation of the free peptide. Measurements of NOESY cross-peak intensities allowed us to determine the spatial structure of the peptide bound to the antibody.