Domain organization and quaternary structure of the Saccharomyces cerevisiae silent information regulator 3 protein, Sir3p.

The silent information regulator protein 3 (Sir3p) functions in the initiation, propagation, and maintenance of transcriptionally silenced chromatin in Saccharomyces cerevisiae. To better understand the physicochemical basis for its effects on chromatin architecture, recombinant full-length S. cerevisiae Sir3p has been purified to near homogeneity on the large-scale and characterized by ...
circular dichroism, limited protease digestion, and analytical ultracentrifugation. Results indicate that the Sir3p monomer has a unique tripartite domain organization, including a nearly 300-amino-acid residue stretch of intrinsically disordered residues that lies internal to its structured N- and C-terminal regions. Sir3p self-associates extensively in moderate salt and at micromolar protein concentrations producing a broad range of oligomers that sediment from 8 to in excess of 85 S. These results provide new insight into Sir3p domain organization and quaternary structure and support a nucleosome bridging model for Sir3p-dependent regulation of chromatin architecture.
Mesh Terms:
Animals, Cells, Cultured, Chickens, Chromatin, Nucleosomes, Protein Structure, Quaternary, Protein Structure, Secondary, Protein Structure, Tertiary, Recombinant Proteins, Saccharomyces cerevisiae Proteins, Silent Information Regulator Proteins, Saccharomyces cerevisiae, Spodoptera
Biochemistry
Date: Dec. 26, 2006
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