SASDA65: Nucleoplasmin-H5 complex (NP-H5)

基本情報

• 登録情報: データベース: SASBDB / ID: SASDA65

試料

Nucleoplasmin-H5 complex

• NP-H5 (protein), NP-H5, Escherichia coli

• 生物種: Escherichia coli (大腸菌)
• 引用: ジャーナル: J Mol Biol / 年: 2009; タイトル: A mechanism for histone chaperoning activity of nucleoplasmin: thermodynamic and structural models.; 著者: Stefka G Taneva / Sonia Bañuelos / Jorge Falces / Igor Arregi / Arturo Muga / Petr V Konarev / Dmitri I Svergun / Adrián Velázquez-Campoy / María A Urbaneja / ; 要旨: Nucleoplasmin (NP), a histone chaperone, acts as a reservoir for histones H2A-H2B in Xenopus laevis eggs and can displace sperm nuclear basic proteins and linker histones from the chromatin fiber of sperm and quiescent somatic nuclei. NP has been proposed to mediate the dynamic exchange of histones during the expression of certain genes and assists the assembly of nucleosomes by modulating the interaction between histones and DNA. Here, solution structural models of full-length NP and NP complexes with the functionally distinct nucleosomal core and linker histones are presented for the first time, providing a picture of the physical interactions between the nucleosomal and linker histones with NP core and tail domains. Small-angle X-ray scattering and isothermal titration calorimetry reveal that NP pentamer can accommodate five histones, either H2A-H2B dimers or H5, and that NP core and tail domains are intimately involved in the association with histones. The analysis of the binding events, employing a site-specific cooperative model, reveals a negative cooperativity-based regulatory mechanism for the linker histone/nucleosomal histone exchange. The two histone types bind with drastically different intrinsic affinity, and the strongest affinity is observed for the NP variant that mimicks the hyperphosphorylated active protein. The different "affinity windows" for H5 and H2A-H2B might allow NP to fulfill its histone chaperone role, simultaneously acting as a reservoir for the core histones and a chromatin decondensing factor. Our data are compatible with the previously proposed model where NP facilitates nucleosome assembly by removing the linker histones and depositing H2A-H2B dimers onto DNA.

登録者

• Petr Konarev (EMBL-Hamburg, European Molecular Biology Laboratory (EMBL) - Hamburg outstation, Notkestraße 85, Geb. 25A, 22607 Hamburg, Deutschland, Germany)

モデル

• モデル #96: ; タイプ: dummy / ソフトウェア: MONSA / ダミー原子の半径: 1.90 A / 対称性: P5 / カイ2乗値: 2.259009; Omokage検索でこの集合体の類似形状データを探す (詳細)

試料

• 試料: 名称: Nucleoplasmin-H5 complex / Sample MW: 200 kDa / 試料濃度: 3.00-5.00
• バッファ: 名称: 20 mM Pipes buffer / pH: 7.5 / 組成: NaCl 150.000 mM
• 要素 #79: 名称: NP-H5 / タイプ: protein / 記述: NP-H5 / 分子量: 40 / 分子数: 5 / 由来: Escherichia coli

実験情報

• ビーム: 設備名称: DORIS III X33 / 地域: Hamburg / 国: Germany / 形状: 0.6 / 線源: X-ray synchrotronシンクロトロン / 波長: 0.15 Å / スペクトロメータ・検出器間距離: 2.7 mm
• 検出器: 名称: Pilatus 1M-W / Pixsize x: 0.172 mm

スキャン

タイトル: NP-H5 / 測定日: 2007年12月3日 / 保管温度: 10 °C / セル温度: 10 °C / 照射時間: 15 sec. / フレーム数: 4 / 単位: 1/nm /

	Min	Max
Q	0.0503	5.1869

結果

カーブのタイプ: single_conc /

	実験値	Porod
分子量	200 kDa	-
体積	-	410 nm3

	Guinier	P(R)
前方散乱 I0	0.474	-
慣性半径, Rg	5.2 nm	5.22 nm

	Min	Max
D	-	16.7
Guinier point	51	77