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D E Kamashev

Publications and source records attributed to D E Kamashev.

7 recordsLinked to original sources
PubMed2000

Tramtrack protein-DNA interactions. A cross-linking study.

Interaction of the Tramtrack protein from Drosophila melanogaster with DNA was analyzed by a cross-linking method. Tramtrack residues cross-linkable to the partially depurinated DNA were identified by direct sequencing. The N-terminal alpha-amino group of the protein DNA-binding domain was found to be the major product of cross-linking. The location of the N terminus on the DNA was determined by identification of the DNA bases that were cross-linked to the protein alpha-amino group. We conclude that accessory N-terminal peptide preceding the first zinc finger of Tramtrack directly interacts with DNA, both in specific and nonspecific DNA-protein complexes. Our finding explains the role in the protein binding of the DNA bases outside of the direct interaction with the zinc fingers.

Amino Acid Sequence↗
PubMed1995

Mechanism of Lac repressor switch-off: orientation of the Lac repressor DNA-binding domain is reversed upon inducer binding.

Lac repressor's DNA-binding domains contain helix-turn-helix motif which, though similar to those of phage lambda Cro protein, are oriented differently with respect to DNA: in the specific complexes with Lac operator, N termini of the repressor's subunits are facing inwards. We demonstrate that, in the presence of an inducer, the repressor's N termini cross-link to the operator's outermost nucleotides. We suggest that the inducer fixes the repressor's DNA-binding domains in the Cro-type configuration and thus garbles its recognition surface. Since the Cro-type configuration is perfectly suitable for binding the DNA, this also explains how the switched-off repressor retains its non-specific DNA-binding.

Amino Acid Sequence↗
PubMedDate not supplied

[Analysis of peculiarities in nucleotides disposition in the origin of chromosome replication-oriC from Escherichia coli].

Along with symmetrical features (palindromes, direct and inverted repeats), periodicities in the disposition of nucleotides in the origin of chromosome replication oriC from E. coli were studied by means of Fourier analysis. Peaks corresponding to the periods T = 2, 17, 95-100 nucleotides are the highest in the Fourier spectrum of oriC. Peaks corresponding to the periods T = 3, 11, 19, 13, 24, 27, 28, 41, 79-81 nucleotides are also prominent, but not so high. Thus, the main periodicities of the oriC spectrum of are not multiple of the B-DNA sugar-phosphate backbone period, which destabilize DNA at oriC and contributes to the spontaneous unwinding of DNA. The differences between the Fourier spectrum of oriC and those of regions adjacent to oriC are demonstrated.

DNA Replication↗
PubMedDate not supplied

[Effect of an inducer on orientation of the DNA-binding domain of the Lac repressor].

We have identified the lac repressor amino acids which form cross-links with partially depurinated DNA and hence are proximate to it. Only lysine-33 is cross-linkable in specific complex with lac operator. At the presence of inducer molecules lysine-33 remains cross-linkable. However, the N-terminal alpha-aminogroup was additionally cross-linked with the boundaries of lac operator. We conclude that orientation of the DNA-binding domain of the repressor is reversed by inducer binding.

Amino Acid Sequence↗
PubMedDate not supplied

[Electrostatic interaction and differences in specific and nonspecific interactions of the Lac-repressor with DNA].

To investigate the complexes of lac-repressor with specific and non-specific DNA sequences method of covalent cross-linking of proteins to partially depurinated DNA was used. We have identified the amino acid resides which form cross-links and hence are proximate to DNA. Only lysine 33 is cross-linkable in specific complex. In the case of non-specific complex (at the presents of inducer molecules) lysine 33 remains cross-linkable. Some consequences of these phenomena in aspects of the physical backgrounds of protein-DNA interactions have been discussed.

Amino Acid Sequence↗