2gcj
From Proteopedia
Crystal Structure of the Pob3 middle domain
Structural highlights
Function[POB3_YEAST] Component of the FACT complex, a general chromatin factor that acts to reorganize nucleosomes. The FACT complex is involved in multiple processes that require DNA as a template such as mRNA elongation, DNA replication and DNA repair. During transcription elongation the FACT complex acts as a histone chaperone that both destabilizes and restores nucleosomal structure. It facilitates the passage of RNA polymerase II and transcription by promoting the dissociation of one histone H2A-H2B dimer from the nucleosome, then subsequently promotes the reestablishment of the nucleosome following the passage of RNA polymerase II. Transcription elongation is promoted by the repression of transcription initiation from cryptic sites. Also acts in establishing transcription initiation complexes and promotes SPT15/TBP-binding to a TATA box. Together with replication factor-A protein (RPA), FACT may play a role in nucleosome deposition during DNA replication.[1] [2] [3] [4] [5] [6] [7] [8] [9] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedWe report the crystal structure of the middle domain of the Pob3 subunit (Pob3-M) of S. cerevisiae FACT (yFACT, facilitates chromatin transcription), which unexpectedly adopts an unusual double pleckstrin homology (PH) architecture. A mutation within a conserved surface cluster in this domain causes a defect in DNA replication that is suppressed by mutation of replication protein A (RPA). The nucleosome reorganizer yFACT therefore interacts in a physiologically important way with the central single-strand DNA (ssDNA) binding factor RPA to promote a step in DNA replication. Purified yFACT and RPA display a weak direct physical interaction, although the genetic suppression is not explained by simple changes in affinity between the purified proteins. Further genetic analysis suggests that coordinated function by yFACT and RPA is important during nucleosome deposition. These results support the model that the FACT family has an essential role in constructing nucleosomes during DNA replication, and suggest that RPA contributes to this process. The structure of the yFACT Pob3-M domain, its interaction with the DNA replication factor RPA, and a potential role in nucleosome deposition.,VanDemark AP, Blanksma M, Ferris E, Heroux A, Hill CP, Formosa T Mol Cell. 2006 May 5;22(3):363-74. PMID:16678108[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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