Biophysical characterization of the association of histones with single-stranded DNA.
Biochim Biophys Acta Gen Subj
; 1861(11 Pt A): 2739-2749, 2017 Nov.
Article
em En
| MEDLINE
| ID: mdl-28756274
BACKGROUND: Despite the profound current knowledge of the architecture and dynamics of nucleosomes, little is known about the structures generated by the interaction of histones with single-stranded DNA (ssDNA), which is widely present during replication and transcription. METHODS: Non-denaturing gel electrophoresis, transmission electron microscopy, atomic force microscopy, magnetic tweezers. RESULTS: Histones have a high affinity for ssDNA in 0.15M NaCl ionic strength, with an apparent binding constant similar to that calculated for their association with double-stranded DNA (dsDNA). The length of DNA (number of nucleotides in ssDNA or base pairs in dsDNA) associated with a fixed core histone mass is the same for both ssDNA and dsDNA. Although histone-ssDNA complexes show a high tendency to aggregate, nucleosome-like structures are formed at physiological salt concentrations. Core histones are able to protect ssDNA from digestion by micrococcal nuclease, and a shortening of ssDNA occurs upon its interaction with histones. The purified (+) strand of a cloned DNA fragment of nucleosomal origin has a higher affinity for histones than the purified complementary (-) strand. CONCLUSIONS: At physiological ionic strength histones have high affinity for ssDNA, possibly associating with it into nucleosome-like structures. GENERAL SIGNIFICANCE: In the cell nucleus histones may spontaneously interact with ssDNA to facilitate their participation in the replication and transcription of chromatin.
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Base de dados:
MEDLINE
Assunto principal:
DNA de Cadeia Simples
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Cromatina
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Histonas
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Fenômenos Biofísicos
Tipo de estudo:
Risk_factors_studies
Idioma:
En
Revista:
Biochim Biophys Acta Gen Subj
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Alemanha