[Kinetics and mechanism of peptide synthesis in solution].

The kinetics of the reaction of Boc-Xaa fluorophenyl esters (where Xaa = Ala, Val, Phe, Ser, Leu, Gly, Met, Pro, or Ile) with leucinamide was studied measuring changes in the fluorescence emission at 375 nm of the fluorophenyl chromophore accompanying the reaction. It was found that the experimental kinetic data couldn't be described by a simple scheme of the second order reaction. The measurements of the kinetic parameters of the reaction at various initial concentrations of reagents indicated that the reaction rate can be expressed as: v = kCNaCAEb, where k is the reaction rate constant, CN is the concentration of leucinamide, and LeuNH2, CAE is the concentration of fluorophenyl ester.

[Use of method of protein engineering in studying calcium-binding proteins].

Major results of the use of protein engineering methods in studies of calcium-binding proteins with the highest affinity for calcium and known three-dimensional structure (parvalbumin, calmodulin, troponin C, calbindin, recoverin, alpha-lactalbumin, and others) are presented. Specific features of recombinant calcium-binding proteins are discussed. Experiments with genetic introduction of fluorescent probes, tryptophan and tyrosine, into proteins are overviewed.

[Point amino acid substitutions in Ca2+-binding centers of recoverin. III. Mutant with the fourth reconstructed Ca2+-binding site].

Unlike wild type recoverin with only two (the second and the third) functioning Ca(2+)-binding sites out of four potential ones, the +EF4 mutant contains a third active Ca(2+)-binding site. This site was reconstructed from the fourth potential Ca(2+)-binding domain by the introduction of several amino acid substitutions in it by site-directed mutagenesis. The effect of these mutations in the fourth potential Ca(2+)-binding site of myristoylated recoverin on the structural features and conformational stability of the protein was studied by fluorimetry and circular dichroism.

[Single amino acid substitutions in the Ca2+-binding site of recoverin.II.The unusual behavior of the protein upon the binding of calcium ions].

The structural properties of myristoylated forms of recombinant recoverin of the wild type and of its mutants with damaged second and/or third Ca(2+)-binding sites were studied by fluorimetry and circular dichroism. The interaction of wild-type recoverin with calcium ions was shown to induce unusual structural rearrangements in its molecule. In particular, protein binding with Ca2+ ions results in an increase in the mobility of the environment of Trp residues, in higher hydrophobicity, and in elevated thermal stability (its thermal transition shifts by 15 degrees C to higher temperatures) but has almost no effect on its secondary structure.

[p-Sulfotetrafluorophenyl hydrophilic activated esters of amino acids in peptide synthesis].

Highly reactive hydrophilic (i.e., water-soluble) p-sulfotetrafluorophenyl esters (Tfs esters) are proposed for peptide synthesis in aqueous and aqueous-organic media, as well as for protein and peptide partial synthesis in an aqueous medium.