Identification of distinct SET/TAF-Iβ domains required for core histone binding and quantitative characterisation of the interaction

Background The assembly of nucleosomes to higher-order chromatin structures is finely tuned by the relative affinities of histones for chaperones and nucleosomal binding sites. The myeloid leukaemia protein SET/TAF-Iβ belongs to the NAP1 family of histone chaperones and participates in several chrom...

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Bibliographic Details
Published in:BMC biochemistry 2009-04, Vol.10 (10), p.10-10, Article 10
Main Authors: Karetsou, Zoe, Emmanouilidou, Anastasia, Sanidas, Ioannis, Liokatis, Stamatis, Nikolakaki, Eleni, Politou, Anastasia S, Papamarcaki, Thomais
Format: Article
Language:English
Subjects:
Histones
Nucleosomes
Physiological aspects
Properties
Protein binding
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Summary:Background The assembly of nucleosomes to higher-order chromatin structures is finely tuned by the relative affinities of histones for chaperones and nucleosomal binding sites. The myeloid leukaemia protein SET/TAF-Iβ belongs to the NAP1 family of histone chaperones and participates in several chromatin-based mechanisms, such as chromatin assembly, nucleosome reorganisation and transcriptional activation. To better understand the histone chaperone function of SET/TAF-Iβ, we designed several SET/TAF-Iβ truncations, examined their structural integrity by circular Dichroism and assessed qualitatively and quantitatively the histone binding properties of wild-type protein and mutant forms using GST-pull down experiments and fluorescence spectroscopy-based binding assays. Results Wild type SET/TAF-Iβ binds to histones H2B and H3 with K.sub.d values of 2.87 and 0.15 μM, respectively. The preferential binding of SET/TAF-Iβ to histone H3 is mediated by its central region and the globular part of H3. On the contrary, the acidic C-terminal tail and the amino-terminal dimerisation domain of SET/TAF-Iβ, as well as the H3 amino-terminal tail, are dispensable for this interaction. Conclusion This type of analysis allowed us to assess the relative affinities of SET/TAF-Iβ for different histones and identify the domains of the protein required for effective histone recognition. Our findings are consistent with recent structural studies of SET/TAF-Iβ and can be valuable to understand the role of SET/TAF-Iβ in chromatin function.
ISSN:1471-2091
1471-2091
DOI:10.1186/1471-2091-10-10