Fração histonica nuclear rica em histona H5 : isolamento, caracterização, orientação macromolecular e interação com DNA

AUTOR(ES)
DATA DE PUBLICAÇÃO

1983

RESUMO

This thesis deals with structural aspects of an H IND. 5 histone rich fraction ( H IND. 5 RF), as well as its importance in the chromatin structure. H IND. 5 RF was extracted from chicken erythrocyte nuclei. Some intrinsic characteristics of H IND. 5 RF a few differenciating qualities in relation to the H IND. 1 histone of the calf thymus were determined by the following methods: an extractive process; absorption espectrophotometry; fluorometry; dye binding as measured by anisotropy and electrophoresis. These were complemented by observations, carried out with the polarization microscope, of chromatin treated with 0,7 NaCl, and stained with toluidine blue or sirius red. H IND. 5 RF-DNA complexes and nuclear material in 0,7M NaCl were studied with the electron microscope. Extraction were made using 5% perchloric acid, 0,7M NaCl and 0,15M NaCl at pH 1,85. This last solution was shown to extract H IND. 5 RF preferencially. No differences were detected in the spectral absorption profiles of H IND. 5 RF and calf thymus H IND. 1 in acid or in alkaline medium. Its is remarkable, however, that the histones, when denatured in a basic medium, were hyperchromic in relation to these some proteins in their native state. In acid medium, the opposite occurred. Fluorescence spectral curves of H IND. 5 RF and calf thymus H IND. 1 solutions indicated a more intense fluorescence for H IND. 5 RF than for H IND. 1 . The fluorescence of denatured H IND. 5 RF was markedly diminished in relation to that in the native condition. No important difference was noted in their spectral absorption profiles... Note: The complete abstract is available with the full electronic digital thesis or dissertations.

ASSUNTO(S)

nucleoproteinas cromatina proteinas cromossomicas não-histonas

ACESSO AO ARTIGO

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