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C Turano

Publications and source records attributed to C Turano.

At least 19 recordsLinked to original sources
PubMed1992

Differential scanning calorimetry of chicken erythrocyte nuclei.

Investigation of structural features of native chromatin requires the use of intact nuclei, a turbid material which cannot be analyzed by optical methods. Differential scanning calorimetry does not require optically clear samples and has been proved by a number of authors to be a powerful tool in this field of study. By this technique, chicken erythrocyte nuclei were found to undergo at least four thermal transitions, centered at 59, 74, 88 and 98 degrees C. The highest temperature transition is strongly dependent on age and storage conditions of the nuclei. Adequate storage conditions overcame this problem and reproducible scans were obtained over a period of several months. This technical improvement has permitted the reconsideration of the occurrence of the fourth calorimetric transition, previously believed to be displayed only in replicating nuclei. Evidence gathered in the presence of perturbants and possible ligands allows the assignment of the four transitions to a nuclear protein scaffold, histones, nucleosomal DNA and a superstructured form of DNA. Moreover, it suggests that the higher-order structure is stabilized by fibronectin-like proteins.

Animals↗
PubMed1992

Crosslinking of nuclear proteins to DNA by cis-diamminedichloroplatinum in intact cells. Involvement of nuclear matrix proteins.

In order to detect the nuclear matrix proteins involved in DNA binding, avoiding possible artifacts derived from the disruption of nuclei, proteins were crosslinked to DNA by the action of cis-diamminedichloroplatinum on intact chicken liver cells and analyzed by two-dimensional gel electrophoresis. At least eleven species of crosslinked proteins were found to derive from the nuclear matrix prepared from the same cell type, and five of these were found also among the proteins crosslinked to DNA in intact liver cells from ox and pig. This subset of common proteins, conserved in different animal species, is likely to have a fundamental role for the anchorage of DNA to the nuclear matrix.

Animals↗
PubMed1992

Isolation of a novel nuclear glycoprotein from pig kidney.

A nuclear glycoprotein with an apparent Mr of 66,000 Da has been isolated from pig kidney chromatin after extraction with urea, guanidine-HCl and 2 M NaCl, and some of its structural features have been characterized. It belongs to the group of N-glycosylated proteins, which in the nucleus has so far received little attention. From its monosaccharide composition and recognition by lectins its oligosaccharides appear to be of high mannose and/or hybrid types. Some properties of its protein moiety suggest that it has a role in the packing of the DNA loops in the condensed chromatin.

Amino Acid Sequence↗
PubMed1991

The presence of N-glycosylated proteins in cell nuclei.

The protein-DNA crosslinking capability of cis-dichloro diammineplatinum has been exploited to check the intranuclear location of N-glycosylated proteins. When intact liver cells were treated with this reagent, a number of glycoproteins, recognized by Concanavalin A, have been shown to become crosslinked to DNA; many of them have been recognized as nuclear matrix components. The recognition by this lectin was abolished by treatment with N-glycosidase F, showing the presence of N-glycosidic bonds between the sugar moiety and the protein. Most of the glycoproteins appeared to have high mannose oligosaccharide chains, but sialic acid containing oligosaccharides were also identified.

Animals↗
PubMed1991

A reverse-phase HPLC method for cAMP phosphodiesterase activity.

A simple and fast method based on reverse-phase HPLC has been developed for measuring the activity of cAMP phosphodiesterase. It allows quantitation of product and substrate in less than 10 min. The sensitivity (1*10(-11) mol AMP), the accurate evaluation of nucleotides, the unequivocal analysis of product, and the reproducibility of the system, make this method suitable for the evaluation of cAMP phosphodiesterase in biological material, at different levels of purification, and also in kinetic studies.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1989

Glycosylated forms of nuclear lamins.

Chromatin and pore complex-lamina preparations were obtained from pig and chicken tissues, and their proteins were analysed by mono- and bidimensional electrophoresis. A glycosylated form of lamin A, recognized by concanavalin A, was shown to be present in at least 3 of the tissues examined. Glycosylation is suggested to be a further postsynthetic modification, besides phosphorylation and methylation, which can modify the properties of lamins.

Animals↗
PubMed1989

Tissue specificity of chromatin glycoproteins recognized by concanavalin A.

Chromatin glycoproteins recognized by Concanavalin A have been isolated from pig liver, kidney and heart by the use of immobilized lectin. Two groups of proteins differing in affinity for DNA have been analysed. Glycoproteins are mainly present in the group of proteins which are tightly bound to DNA. Mono and bidimensional electrophoretic patterns of total tightly bound proteins reveal a similarity among the three organs examined, while the corresponding patterns of the glycoproteins are typical for each organ. The tissue specificity of chromatin glycoproteins, together with their capability to interact not only with DNA but possibly also with other nuclear components, suggest a role for these proteins in the mechanism of genome expression.

Animals↗
PubMed1988

Calorimetric analysis of sodium dodecylsulfate-chromatin interaction.

Microcalorimetric titrations of whole chromatin and histones with sodium dodecylsulfate were performed at pH 7 and 25 degrees C. Enthalpy variations at low detergent concentration (less than 0.02%) are much more negative for histones than for chromatin. At 0.065% sodium dodecylsulfate the difference between the two curves becomes constant and, after correction for monomerization effects, amounts to +130 kcal/mol of nucleosomal unit. Core particles show heat effects similar to those of histones. These findings suggest that the chromatin structure is not stabilized exclusively by electrostatic interactions and that hydrogen bonds responsible for the additional stability may be contributed by non histone chromatin proteins.

Animals↗
PubMed1986

The influence of ionic strength on the binding of a water soluble porphyrin to nucleic acids.

The ionic strength dependences of the binding of tetrakis (4-N-methylpyridyl)porphine (H2TMpyP) to poly(dG-dC) and calf thymus DNA have been determined. For the former system the results are typical of other intercalators, i.e., a plot of log K vs log [Na+] is linear albeit with a slope which suggests that the "effective charge" of the porphyrin is closer to two than the formal charge of +4. For calf thymus DNA, the binding profile is not completely compatible with the predictions of condensation theory. Whereas the avidity of binding does decrease with increasing [Na+] as predicted, of greater interest is the relocation of the porphyrin from GC-rich regions to AT-rich regions as the ionic strength increases.

Animals↗
PubMed1986

Thiol proteins in chromatin.

Total half-cystine residues in proteins of pig liver chromatin have been measured. About half of them are present in the reduced state. Thiol groups of non-histone chromatin proteins, which amount to about 40 nmol/mg of protein, are preferentially located in chromatin fragments which are more easily solubilised either by DNAse I or by DNAse II. The data obtained are compatible with an involvement of SH and SS groups in chromatin structure and function.

Amino Acids↗
PubMed1985

Specific labeling of cytosolic and mitochondrial aspartate aminotransferases.

The apoisozymes of cytosolic and mitochondrial aspartate aminotransferase are both irreversibly inhibited by alpha-N-fluorodinitrophenyl-beta-N-phosphopyridoxyldiaminopropi onate, an affinity-labeling reagent analog of the coenzyme. Analysis of the modified peptides shows that the active-site Lys-258, which in the holoenzyme binds the coenzyme pyridoxal 5'-phosphate, is labeled in both isozymes. Comparison with the results obtained using the parent compound 4'-N-fluorodinitrophenylpyridoxamine 5'-phosphate, which labels only the cytosolic enzyme, provides information about differences in active-site reactivity and geometry. Labeling external to the active site occurs in both isozymes. In the cytosolic enzyme the very reactive Cys-45 is modified, in the mitochondrial enzyme the surface residue Lys-342 reveals a peculiar reactivity.

Affinity Labels↗
PubMed1979

Purification and characterization of 3,4-dihydroxyphenylalanine decarboxyase from pig kidney.

A procedure for 3,4-dihydroxyphenylalanine decarboxylase from pig kkdney purification is described in detail. The preparation has no detectable impurity on electrophoresis and on ultracentrifugation and authors. However two significant differences are observed: a different stimulation of activity by added pyridoxal 5'-phosphate and a nearly complete decarboxylation of L-3,4-dihydroxyphenylalanine in absence of added coenzyme. Absorption, fluorescence and circular dichroism properties of the coenzyme-apoenzyme interaction are also described. The results are consistent with the existence of at least four coenzyme-apoenzyme complexes, three of them active.

Animals↗