[ON CLUPEINES. XIV. ON THE PRESENCE OF INTERMOLECULAR COPPER COMPOUNDS IN CLUPEINE].
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Cell Nucleus↗
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Studies on protamines. XIV. Partial chemical structure of one component of clupeine, clupeine Z.
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Amino Acid Sequence↗
Structure and function of protamines: an 1H nuclear magnetic resonance investigation of the interaction of clupeines with mononucleotides.
Protamines form a class of low-molecular-weight proteins that protect the chromosomal DNA in the spermatic cells of eukaryotic organisms. Protamines are located in the small and/or large groove of DNA where they complex the DNA nucleotides. Very little is known up to date on the role and specificity of binding of the various protamine fractions belonging to a single eukaryotic species. In the present paper, a detailed investigation on the complexation properties of the protamine fractions (clupeines) extracted from herrings has been carried out by means of proton nuclear magnetic resonance and ultraviolet absorbtion data. In particular, the binding properties of the clupeine fractions with purinic (5'dAMP) and pyrimidinic (5'dCMP) mononucleotides have been measured and analysed at different clupeine concentrations. The results indicate that, contrary to previous preliminary hypothesis, the three clupeine fractions exhibit quite comparable binding properties toward mononucleotides. In addition it has been found that nucleotides can induce a conformational transition of the disorder-order type in the clupeine molecules and this property is concentration and temperature dependent. It is concluded that, as far as specificity is concerned, the clupeine fractions seem to possess the same behaviour toward mononucleotides.
Amino Acid Sequence↗
Hydration of clupeine in solution.
Spin-lattice relaxation times, T1, of H2(17) O at 25 degrees were measured for aqueous solutions of clupeine and its constituent amino acids, which are serine, threonine, proline and arginine. The dynamic hydration numbers, nDHN, of clupeine and amino acids were determined from a concentration dependence of T1. The coordination numbers nh, and the rotational correlation times, tau ch, of water molecules around clupeine and amino acids were estimated and compared with that of pure water. The tau ch/tau co of clupeine was 1.85 and close to that of arginine. The experimental value of nDHN of clupeine was in good agreement with that calculated from the nDHN values of the constituent amino acids. This means that the clupeine molecule has a random conformation in solution.
Amino Acid Sequence↗
The effect of clupein on anisotropy and basophilia of polytene chromosomes.
When polytene chromosomes are subjected to a clupein treatment, their properties of basophilia and anisotropy are affected. The basophilia is deeply reduced, except in the nucleolar zones, puffs and sites of RNA accumulation. On the other hand, the chromosome birefringence increases. The phenomenon of anomalous dispersion of birefringence usually observed on polytene chromosomes stained with toluidine blue solutions turns into a normal negative dispersion of birefringence, when staining is preceded by clupein treatment. It is concluded that the clupein molecules attach orderly and preferentially to sequential DNA phosphates unbound to chromosome proteins, accentuating DNA anisotropic characteristics. The clupein molecules appear not attaching to RNA phosphates.
Animals↗
Fluorescence studies on clupein protamines: evidence for globular conformation.
Conjugates of fluorescein isothiocyanate with clupein YI, YII and Z, the protamines from Clupea palasii, were prepared and their fluorescence utilized to determine the rotational relaxation times of the proteins. All conjugates exhibited single component lifetimes near 4.05 ns. Linear isothermal Perrin plots were obtained for all conjugates; these data indicated rotational relaxation times of 3.33 ns for clupein YI and YII and 3.19 ns for clupein Z. These results and the results from our previous studies lead us to postulate globular conformations for the three proteins with hydrated molecular diameters of 22 A. Based on these findings a three dimensional model for Clupein YII is proposed.
Clupeine↗
Protamines. II. Circular dichroism study of the three main components of clupeine.
The three main components YI, YII, and Z of clupeine, a protamine from herring, have been purified and characterized. The conformational preferences of clupeines have been examined as a funciton of pH, temperature, added salts, and presence of structure-disrupting agents and helix-supporting solvents using circular dichroism. It was found that these small basic proteins assume predominantly an unordered conformation in aqueous solution. Addition of counter ions, in particular perchlorate, and 2-chloroethanol induces in various amounts the onset of the right-handed alpha-helical conformation. Urea favors the statistical coil state. It was also demonstrated that in the 0.1--4.0 . 10(-1) M range, in contrast to clupeines YI and Z, the circular dichroic properties of the YII component do not seem to be sensitive to the addition of mono- and diphosphate.
Amino Acids↗
Nuclear magnetic resonance of protamines. A 1H-NMR study of the interaction of clupeine fractions with mononucleotides.
The interaction of the three clupeine fractions, YI, YII, Z, and salmine fraction AI with mononucleotides has been examined by means of 1H nuclear magnetic resonance. The results obtained are interpreted in terms of electrostatic interactions between positive arginine guanidinyl groups and negative nucleotide phosphates. In addition, clupeine fraction YI and salmine fraction AI exhibit with guanine and adenine nucleotides a more specific interaction that leads to the formation of large aggregates in solution. The experimental data presented in this work demonstrate that the strength of interaction between clupeine YI and salmine AI with mononucleotides follows the order: 5'-dTMP approximately equal to 5'-dCMP much less than 5'-dAMP less than 5'-dGMP approximately equal to 5'-GMP.
Adamantane↗
13C Nuclear magnetic resonance of protamines. The three main components of clupeine.
The three main components (called YI, YII and Z) of clupeine a protamine from herring have been isolated and characterized by 13C nuclear magnetic resonance. Resonance belonging to the many different amino acid carbon atoms are observable and assigned. The effect of urea on the clupeine fractions points to the molecules being essentially in extended form in 2H2O solutions. Unusual properties of clupeine fractions can be observed in the presence of phosphate. Two of the fractions, i.e. YI and Z, show that a partial folding occurs in some well-defined whereas fraction YII remains essentially unaltered.
Animals↗
Interaction of the three main components of clupeine with glycosaminoglycans.
The interactions between each of the three main components of clupeine (YI, YII and Z) and the glycosaminoglycans chondroitin sulfate, heparin and hyaluronic acid were studied with circular dichroism spectroscopy. The induced dichroism is a measure of relative complex stability, which increases with the number of sulfate groups on the glycosaminoglycan. Measuring the induced dichroism as a function of mole ratio of disaccharide to arginine establishes the stoichiometry of the complexes. For a given glycosaminoglycan, the induced dichroism depends on the clupeine, increasing the order YI less than YII less than Z.
Chondroitin Sulfates↗
Nuclear magnetic resonance of protamines. A 13C relaxation study of the three main fractions of clupeine.
The three main fractions of clupeine, the protamine extracted from herring sperm, have been investigated by 13C nuclear magnetic resonance techniques. The dynamic behaviour, examined through the evaluation of the spin lattice relaxation times (T1) of individual carbon resonances assigned to both backbone and side chains, reveals interesting features. The relaxation times of backbone alpha-carbons, interpreted on the basis of an axially symmetric ellipsoid, point to the clupeine fractions as being essentially extended in aqueous solution. These times remain constant along the polypeptide chain and are of the order of 0.16 +/- 0.02 s. Conversely, the side chains show different flexibilities in the presence of monophosphate counterions, thus demonstrating a diverging behaviour which may be biologically relevant. In particular, the side-chain flexibilities of fraction YI decrease, while those of fractions Z and YII are either constant or increase. Comparison of these data with the viscosity measurements helps in explaining the viscosity changes observed in the presence of phosphate.
Amino Acid Sequence↗
Cooperative binding of fluorescein-labeled clupeine by DNA.
The alpha-amino group of clupeine fraction Z from herring sperm was coupled with fluorescein. Binding of the labeled protamine by DNA is accompanied by significant fluorescence quenching up to 80%. This allowed the convenient determination of the binding behavior of protamine and DNA. Binding was found to be strongly cooperative and not be significantly affected by the size of DNA. The ionic strength dependence in the range up to 0.3 M NaCl was rather small. Binding parameters were derived according to classical unique-site treatment and to a concept which includes vagrant multi-site binding.
Binding Sites↗
Preparation and conformational study of clupeine fragments.
Fragments of clupeines, YI, YII, and Z of divergent chain length and different amino acid composition were prepared by digestion with thermolysin and a mixture of carboxypeptidases A and B, and their conformational preferences examined as a function of pH, added salts, presence of a helix-supporting solvent, and temperature. All these highly basic oligopeptides adopt an essentially unordered conformation in aqueous solution. 2-Chloroethanol supports in various amounts the onset of the right-handed alpha-helical form in the carboxy-peptidase fragments.
Amino Acid Sequence↗
[Molecular analysis of clupeine].
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Clupeine↗
Peptides obtained by tryptic digestion of clupeine.
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Clupeine↗
The chemical structure of one component of clupeine.
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Clupeine↗