title: Structure of the Spt16 middle domain reveals functional features of the histone chaperone FACT.
abstract: The histone chaperone FACT is an essential and abundant heterodimer found in all eukaryotes. Here we report a crystal structure of the middle domain of the large subunit of FACT (Spt16-M) to reveal a double pleckstrin homology architecture. This structure was found previously in the Pob3-M domain of the small subunit of FACT and in the related histone chaperone Rtt106, although Spt16-M is distinguished from these structures by the presence of an extended α-helix and a C-terminal addition. Consistent with our finding that the double pleckstrin homology structure is common to these three histone chaperones and reports that Pob3 and Rtt106 double pleckstrin homology domains bind histones H3-H4, we also find that Spt16-M binds H3-H4 with low micromolar affinity. Our structure provides a framework for interpreting a large body of genetic data regarding the physiological functions of FACT, including the identification of potential interaction surfaces for binding histones or other proteins.
authors: Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112-5650, USA.
authors: David J
authors: DJ
authors: Kemble
authors: Frank G
authors: FG
authors: Whitby
authors: Howard
authors: H
authors: Robinson
authors: Laura L
authors: LL
authors: McCullough
authors: Tim
authors: T
authors: Formosa
authors: Christopher P
authors: CP
authors: Hill
mesh_terms: D000818:Animals; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006609:High Mobility Group Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D018832:Molecular Chaperones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D040681:Structural Homology, Protein; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D035602:Transcriptional Elongation Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; C541535:FACT protein, S cerevisiae; D006609:High Mobility Group Proteins; D018832:Molecular Chaperones; C106768:POB3 protein, S cerevisiae; C505157:Rtt106 protein, S cerevisiae; C071238:SPT16 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors