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The interaction of nucleoside diphosphate kinase with purinic and pyrimidinic nucleotides: a calorimetric study.
No full textNDPK/NM23 I: calorimetric studies of conformational stability and substrate affinity of Nucleoside Diphosphate Kinase.
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DOMAINS IN BOVINE SERUM AMINE OXIDASE
No full textAnalysis of the thermal unfolding of bovine serum amine oxidase by differential scanning calorimetry reveals for the dimeric protein a four domain structure consisting of two sets of domains. Each set contains two domains of similar size. The two smaller domains, in contrast with the larger ones, greatly differ in thermostability. Removal of copper changes the calorimetric pattern dramatically. The findings confirm that the metal cofactor plays a structural role. Since the enzyme contains two copper atoms and only one titratable carbonyl group, the calorimetric pattern suggests that the difference in thermostability of the two small domains might be due to the presence of a single organic cofactor. © 1988
Thermodynamics of nucleotide binding to nucleoside diphosphate kinase determined by titration calorimetry.
No full textCALORIMETRIC ANALYSIS OF SODIUM DODECYLSULFATE-CHROMATIN INTERACTION
No full textMicrocalorimetric 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
Binding of nucleoside diphosphate kinase to DNA in vivo.
No full textIn caso di "Asbtract di comunicazione a congresso" l'autore dovrà inserire un abstract dell'abstract: ma gli abstract avranno un valore nella prossima VQR
Stability of Japanese-lacquer-tree (Rhus vernicifera) laccase to thermal and chemical denaturation: comparison with ascorbate oxidase.
No full textThe thermal denaturation of laccase from the Japanese lacquer tree (Rhus vernicifera) was studied by differential scanning calorimetry. The endotherms of holo-laccase, type 2-Cu-depleted laccase and apo-laccase were deconvoluted into two independent two-state transitions, providing evidence for a domain structure of the protein. The correlation of the two transitions with the bleaching of copper optical bands and the decrease of the transitions' enthalpy on Cu removal show that the process involves the denaturation of Cu sites. No detectable unfolding of secondary structure was observed, since the thermal transitions, characterized by low overall specific enthalpy, did not modify either the laccase c.d. spectra in the beta-fold region or the maximum wavelength of the fluorescence emission. On chemical denaturation, however, the emission was red-shifted by about 20 nm. The laccase behaviour is substantially different from that of stellacyanin, a protein containing a single blue Cu ion, in which the thermal transition had higher specific enthalpy and induced a large change of the c.d. spectrum in the beta-fold region. The laccase denaturation behaviour is similar to that of ascorbate oxidase from zucchini (courgette; Cucurbita pepo) [Savini, D'Alessio, Giartosio, Morpurgo and Avigliano (1990) Eur. J. Biochem. 190, 491-495], suggesting a structural analogy. In both proteins heating may cause a change of tertiary structure through modifications of Cu co-ordination with loosening of the bonds between the structural domains at the interface of which the trinuclear Cu cluster is located
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