Search PubMed⌕ Search

Biomedical subjects

V V Shik

Publications and source records attributed to V V Shik.

11 recordsLinked to original sources
PubMed1980

[Interaction of histones with DNA in chromatin. A new method of covalent binding of histones to DNA available for their localization on DNA].

A new method for covalent binding of histones to partially apurinized DNA was developed. Partial apurinization of DNA methylated within the composition of chromatin results in a formation of aldehyde groups interacting with the epsilon-amino groups of chromatin proteins lysine residues. The resulting Schiff's bases covalently and reversibly bind the protein molecules to DNA. This covalent binding is accompanied by a specific one-chain cleavage of DNA at the cross-linkage point in such a way that only the newly formed 5'-terminal fragment of DNA in bound to the protein. These cross-links can be stabilized via reduction of Schiff's bases by sodium borohydrate. Determination of the size of the bound DNA fragment allows to establish the localization of the cross-linkage point and the position of the protein molecule on DNA. The method of cross-linkage with a "zero length" allows to fix the immediate DNA--protein interactions and can be extensively used to study the protein--DNA interactions in cases when the epsilon-amino groups of protein lysine residues interact with DNA.

Animals↗
PubMedDate not supplied

[Chromosomal proteins in chick embryo erythrocytes on transcriptionally active and inactive genes].

Using chicken embryonic erythrocytes as a model, an experimental scheme for comparing the density of linker histones and high mobility group proteins on single-copy sequences of eukaryotic genome has been developed, thus permitting to probe alterations in the chromosomal protein pattern of transcribing chromatin. The report provides experimental evidence for validity of intracellular DNA-protein cross-linking, immunoaffinity chromatography and hybridization with single-stranded probes. Depletion of linker histones and enrichment of HMG 14/17 were shown to be the discriminating feature for transcriptionally active globin gene chromatin as opposed to inactive ovalbumin and lysozyme gene chromatin.

Animals↗
PubMedDate not supplied

[State of DNA slots in mono- and oligonucleosomes and in DNA complexes with individual histones].

The state of the major and the minor DNA grooves in purified mono- and oligonucleosomes and in the complexes of DNA with different histones have been studied by means of methylation of DNA with dimethyl sulphate. In nucleosomes histones shielded major groove by 18--20%. This result agrees well with our previous data obtained with chromatin, nuclei and whole cells. Each of the purified histones H2a, H2b, H3 and H4 as well as N-terminal peptides of H4 histone cause relative shielding of the DNA major groove by 15--18% like whole histone does. H1 histone protects neither DNA grooves from methylation. Our results suggest that histones are buried partly in the major groove of DNA in chromatin and purified nucleosomes. The arrangement of histones in the major groove does not depend probably on their specific organization in nucleosomes.

Animals↗
PubMedDate not supplied

[Primary organization of nucleosome core particles in active and repressed nuclei].

A refined high-resolution map for the linear arrangement of histones along DNA in the nucleosomal core particles has been determined by DNA-protein crosslinking. Histones are aligned on one strand of the 145 bp core DNA in the following order: (5') H2B25,35--H455,65--H375,85,, 95/H488--H2B105, 115--H2A118--H3135, 145/H2A145 (3') (the subscripts indicate the approximate distance in nucleotides of the main histone binding sites from the 5'-end of the core DNA). This suggests a symmetrical and rather autonomous arrangement of the histone tetramer (H3, H4)2 and two dimers (H2A, H2B) on the double-stranded core DNA: H2A/H3--(H2A, H2B)--(H3, H4)2--(H2B, H2A)--H3/H2A. The arrangement of histones on DNA was found to be very similar for the cores isolated from the repressed nuclei of sea urchin sperm and chicken erythrocytes and from the active in transcription and replication Drosophila embryo and yeast nuclei. This indicates that the core nucleosome structure is highly conserved through evolution and that the overall inactivation of chromatin does not affect the primary organization of the cores. A new binding site H2B58 was found for a sea urchin spermal variant of H2B which contains an additional basic segment within the N-terminal part of the molecule. The core isolation procedure was shown to introduce changes into the core structure which are reflected in the appearance of a new binding site H2A75.

Amino Acid Sequence↗
PubMedDate not supplied

[Contacts of Escherichia coli RNA polymerase subunits with nucleotides of lacUV5 promoter].

We have localized contacts between DNA and subunits of E. coli RNA polymerase (of both holo and core enzymes) along lacUV5 promoter. In the complex with the holo enzyme the anti-sense strand of DNA makes contacts with beta' subunit at -47, -46, -30, -12, +1, +5, +7, +9; beta subunit at -30, -25, -23, -12, +11, +30 and delta subunit at -17, -5, -3 nucleotides, while the sense-strand of DNA makes contacts with beta' subunit at -22, -21, -9, -6, -4, +3, +4, +6, +17; beta subunit at +17, +25, +27, +34; and delta subunit at -35, -18 nucleotides. In the complex with the core enzyme the anti-sense strand of DNA makes contacts with beta'subunit at -47, -23, -5, -3, +5, +7, +9; beta subunit at -23, -16, +11, +30 nucleotides while the sense-strand of DNA makes contacts with beta' subunit at -20, -19, +3, +4, +6, +17; beta subunit at -36, -35, -34, -31, -29, +17, +25, +27, +34 nucleotides alpha subunits of the holo as well as the core enzyme show no contact with DNA in the conditions providing specific complex formation.

Base Sequence↗