4eo5 | pdb_00004eo5

Yeast Asf1 bound to H3/H4G94P mutant

spinqualitylabelsall models 4eo5, resolution 2.35Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4eo5 is a 3 chain structure with sequence from Atcc 18824 and African clawed frog. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ACT, GOL Gene: ASF1, CIA1, YJL115W, J0755 (ATCC 18824) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [ASF1_YEAST] Histone chaperone that facilitates histone deposition and histone exchange and removal during nucleosome assembly and disassembly. Facilitates histone deposition through both replication-dependent and replication-independent chromatin assembly pathways. Cooperates with chromatin assembly factor 1 (CAF-1) to promote replication-dependent chromatin assembly and with the HIR complex to promote replication-independent chromatin assembly, which may occur during transcription and DNA repair. May be required for the maintenance of a subset of replication elongation factors, including DNA polymerase epsilon, the RFC complex and PCNA, at stalled replication forks. Also required for acetylation of histone H3 on 'Lys-9' and 'Lys-56'. [H4_XENLA] Core component of nucleosome. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling. [H32_XENLA] Core component of nucleosome. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling. Publication Abstract from PubMed ABSTRACT: BACKGROUND: The protein anti-silencing function 1 (Asf1) chaperones histones H3/H4 for assembly into nucleosomes every cell cycle as well as during DNA transcription and repair. Asf1 interacts directly with H4 through the C-terminal tail of H4, which itself interacts with the docking domain of H2A in the nucleosome. The structure of this region of the H4 C-terminus differs greatly in these two contexts. RESULTS: To investigate the functional consequence of this structural change in histone H4, we restricted the available conformations of the H4 C-terminus and analyzed its effect in vitro and in vivo in S. cerevisiae. One such mutation, H4 G94P, had modest effects on the interaction between H4 and Asf1. However, in yeast, flexibility of the C-terminal tail of H4 has essential functions that extend beyond chromatin assembly and disassembly. The H4 G94P mutation resulted in severely sick yeast although, nucleosomes still formed in vivo albeit yielding diffuse micrococcal nuclease ladders. In vitro, H4G4P had modest effects on nucleosome stability, dramatically reduced histone octamer stability, and altered nucleosome sliding ability. CONCLUSIONS: The functional consequences of altering the conformational flexibility in the C-terminal tail of H4 are severe. Interestingly, despite the detrimental effects of the histone H4 G94P mutant on viability, nucleosome formation was not markedly affected in vivo. However, histone octamer stability and nucleosome stability as well as nucleosome sliding ability were altered in vitro. These studies highlight an important role for correct interactions of the histone H4 C-terminal tail within the histone octamer and suggest that maintenance of a stable histone octamer in vivo is an essential feature of chromatin dynamics. The conformational flexibility of the C-terminus of histone H4 promotes histone octamer and nucleosome stability and yeast viability.,Chavez MS, Scorgie JK, Dennehey BK, Noone SM, Tyler JK, Churchill ME Epigenetics Chromatin. 2012 Apr 27;5(1):5. PMID:22541333 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Anti-silencing factor Histone

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