ABSTRACT
Models of chromatin fibers structures with linear regions of linker DNA were analysed. Limitations put by end dimensions of linker DNA and nucleosomes are considered. Good agreement between the structural properties of model and real chromatin fibers was obtained. It has been shown that the models with three and more configurations of closely located nucleosomes have linker DNA of 19-53 base pairs length, which is characteristic of real chromatin of the majority of somatic cells.
Subject(s)
Chromatin , DNA , Models, Molecular , Nucleic Acid Conformation , Nucleosomes , Protein ConformationABSTRACT
Surface conductivity (SC) of the double layer at the phospholipid liposome surface has been examined with quasi-elastic light scattering technique combined with pulse electrophoresis. 23Na NMR was used to study the interaction between sodium ions and liposomes. The migration of bound ions along the surface was shown to produce the main contribution to SC. The constants of binding the sodium ion to phospholipid heads were found to be 6 M-1 for phosphatidylserine and 80 M-1 for phosphatidyl acid. The exchange rate of ions bound to the lipid was estimated at 10(10) s-1.
Subject(s)
Liposomes , Light , Magnetic Resonance Spectroscopy , Phosphatidic Acids , Phosphatidylserines , Scattering, Radiation , Sodium , Surface PropertiesSubject(s)
DNA, Viral , Spermidine , Chemical Phenomena , Chemistry , Microscopy, Electron , Spectrum Analysis , T-Phages/analysisSubject(s)
Affinity Labels , Cytochrome P-450 Enzyme System , Imines , Microsomes, Liver/metabolism , Animals , Free Radicals , Kinetics , Microwaves , Protein Binding , RatsABSTRACT
The Cu(Lys)2 complex is shown to be an effective inhibitor of the oxidation of 3,4-benzpyrene and aniline in microsomes. Apparently, this is due to the dismutation of superoxide radicals involved in the metabolism of these compounds. Possible interactions between Cu(Lys)2 and model membranes have been studied using spin probes. A model has been suggested according to which Cu(Lys)2 "builds" in the membrane hydrocarbon regions.
Subject(s)
Aniline Compounds/metabolism , Benzopyrenes/metabolism , Cytochrome P-450 Enzyme System/metabolism , Microsomes, Liver/metabolism , Animals , Carbon Monoxide , Copper/pharmacology , Electron Spin Resonance Spectroscopy , Kinetics , Lysine/pharmacology , Male , NADPH-Ferrihemoprotein Reductase/metabolism , Oxidation-Reduction , Rats , SpectrophotometryABSTRACT
To detect changes in the oxygen concentration during biochemical reactions, the exchange broadening in the ESR spectra of nitroxide radicals caused by the dissolved oxygen, has been used. The measurements have been carried out using changes in the width either of the proton hyperfine structure components or of the nitrogen hyperfine structure line with an unresolved proton structure. Detection of mitochondrial respiration in a volume of about 10(-3) cm 3 and respiration for 100 +/- 5 liver cells in a volume of about 10(-4) cm3 has been carried out.
Subject(s)
Oxygen , Spin Labels , Electron Spin Resonance Spectroscopy/methods , Kinetics , Mathematics , Oxygen/metabolismABSTRACT
It is shown that the ESR spectra of triple-stranded complex formed by the polyribouridylic acid with the trideoxyadenylate spin-labelled on terminal phosphate is a superposition of the signals with strongly different width of HFS-components. This result is a structural support of the early proposed supposition about the irregular relative orientations of the oligomers in the triple-stranded complexes of oligoadenylates with poly-U.
