2io5
From Proteopedia
(New page: 200px<br /><applet load="2io5" size="450" color="white" frame="true" align="right" spinBox="true" caption="2io5, resolution 2.700Å" /> '''Crystal structure o...) |
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| - | [[Image:2io5.jpg|left|200px]]<br /><applet load="2io5" size=" | + | [[Image:2io5.jpg|left|200px]]<br /><applet load="2io5" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2io5, resolution 2.700Å" /> | caption="2io5, resolution 2.700Å" /> | ||
'''Crystal structure of the CIA- histone H3-H4 complex'''<br /> | '''Crystal structure of the CIA- histone H3-H4 complex'''<br /> | ||
==Overview== | ==Overview== | ||
| - | CIA (CCG1-interacting factor A)/ASF1, which is the most conserved histone | + | CIA (CCG1-interacting factor A)/ASF1, which is the most conserved histone chaperone among the eukaryotes, was genetically identified as a factor for an anti-silencing function (Asf1) by yeast genetic screening. Shortly after that, the CIA-histone-H3-H4 complex was isolated from Drosophila as a histone chaperone CAF-1 stimulator. Human CIA-I/II (ASF1a/b) was identified as a histone chaperone that interacts with the bromodomain-an acetylated-histone-recognizing domain-of CCG1, in the general transcription initiation factor TFIID. Intensive studies have revealed that CIA/ASF1 mediates nucleosome assembly by forming a complex with another histone chaperone in human cells and yeast, and is involved in DNA replication, transcription, DNA repair and silencing/anti-silencing in yeast. CIA/ASF1 was shown as a major storage chaperone for soluble histones in proliferating human cells. Despite all these biochemical and biological functional analyses, the structure-function relationship of the nucleosome assembly/disassembly activity of CIA/ASF1 has remained elusive. Here we report the crystal structure, at 2.7 A resolution, of CIA-I in complex with histones H3 and H4. The structure shows the histone H3-H4 dimer's mutually exclusive interactions with another histone H3-H4 dimer and CIA-I. The carboxy-terminal beta-strand of histone H4 changes its partner from the beta-strand in histone H2A to that of CIA-I through large conformational change. In vitro functional analysis demonstrated that CIA-I has a histone H3-H4 tetramer-disrupting activity. Mutants with weak histone H3-H4 dimer binding activity showed critical functional effects on cellular processes related to transcription. The histone H3-H4 tetramer-disrupting activity of CIA/ASF1 and the crystal structure of the CIA/ASF1-histone-H3-H4 dimer complex should give insights into mechanisms of both nucleosome assembly/disassembly and nucleosome semi-conservative replication. |
==About this Structure== | ==About this Structure== | ||
| - | 2IO5 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [http://en.wikipedia.org/wiki/Xenopus_laevis Xenopus laevis]. Full crystallographic information is available from [http:// | + | 2IO5 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [http://en.wikipedia.org/wiki/Xenopus_laevis Xenopus laevis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2IO5 OCA]. |
==Reference== | ==Reference== | ||
| - | Structure and function of the histone chaperone CIA/ASF1 complexed with histones H3 and H4., Natsume R, Eitoku M, Akai Y, Sano N, Horikoshi M, Senda T, Nature. 2007 Feb 11 | + | Structure and function of the histone chaperone CIA/ASF1 complexed with histones H3 and H4., Natsume R, Eitoku M, Akai Y, Sano N, Horikoshi M, Senda T, Nature. 2007 Mar 15;446(7133):338-41. Epub 2007 Feb 11. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17293877 17293877] |
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
| Line 21: | Line 21: | ||
[[Category: histone]] | [[Category: histone]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:54:33 2008'' |
Revision as of 15:54, 21 February 2008
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Crystal structure of the CIA- histone H3-H4 complex
Overview
CIA (CCG1-interacting factor A)/ASF1, which is the most conserved histone chaperone among the eukaryotes, was genetically identified as a factor for an anti-silencing function (Asf1) by yeast genetic screening. Shortly after that, the CIA-histone-H3-H4 complex was isolated from Drosophila as a histone chaperone CAF-1 stimulator. Human CIA-I/II (ASF1a/b) was identified as a histone chaperone that interacts with the bromodomain-an acetylated-histone-recognizing domain-of CCG1, in the general transcription initiation factor TFIID. Intensive studies have revealed that CIA/ASF1 mediates nucleosome assembly by forming a complex with another histone chaperone in human cells and yeast, and is involved in DNA replication, transcription, DNA repair and silencing/anti-silencing in yeast. CIA/ASF1 was shown as a major storage chaperone for soluble histones in proliferating human cells. Despite all these biochemical and biological functional analyses, the structure-function relationship of the nucleosome assembly/disassembly activity of CIA/ASF1 has remained elusive. Here we report the crystal structure, at 2.7 A resolution, of CIA-I in complex with histones H3 and H4. The structure shows the histone H3-H4 dimer's mutually exclusive interactions with another histone H3-H4 dimer and CIA-I. The carboxy-terminal beta-strand of histone H4 changes its partner from the beta-strand in histone H2A to that of CIA-I through large conformational change. In vitro functional analysis demonstrated that CIA-I has a histone H3-H4 tetramer-disrupting activity. Mutants with weak histone H3-H4 dimer binding activity showed critical functional effects on cellular processes related to transcription. The histone H3-H4 tetramer-disrupting activity of CIA/ASF1 and the crystal structure of the CIA/ASF1-histone-H3-H4 dimer complex should give insights into mechanisms of both nucleosome assembly/disassembly and nucleosome semi-conservative replication.
About this Structure
2IO5 is a Protein complex structure of sequences from Homo sapiens and Xenopus laevis. Full crystallographic information is available from OCA.
Reference
Structure and function of the histone chaperone CIA/ASF1 complexed with histones H3 and H4., Natsume R, Eitoku M, Akai Y, Sano N, Horikoshi M, Senda T, Nature. 2007 Mar 15;446(7133):338-41. Epub 2007 Feb 11. PMID:17293877
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