Crystal structure of Hsc20, a J-type co-chaperone from Escherichia coli
Crystal structure of Hsc20, a J-type co-chaperone from Escherichia coli
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DOI：
10.1006/jmbi.2000.4252
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发表时间：
2000-12-15
影响因子：
5.6
通讯作者：
Vickery, LE
中科院分区：
文献类型：
--
作者：
Cupp-Vickery, JR;Vickery, LE
Hsc20 是一种 20 kDa T 蛋白，可调节 Hsc66（一种 hsp70 类分子伴侣）的 ATP 酶活性和肽结合特异性。我们在此报道了大肠杆菌 Hsc20 的晶体结构，使用单同晶置换 (SIR) 和多波长异常衍射 (MAD) 的组合确定分辨率为 1.8 埃。 Hsc20的整体结构由两个不同的结构域组成，一个包含残基1-75的N端J结构域通过短环连接到包含残基84-171的C端结构域。 J 结构域的结构涉及与 Hsc66 的相互作用，类似于之前通过溶液 NMR 方法测定的大肠杆菌 DnaJ 和人 Hdj1 的 J 结构域片段的 sc 拓扑。 C 端结构域涉及 Hsc66 蛋白的结合和靶向，由三螺旋束组成，其中两个螺旋构成反平行大肠杆菌。这两个结构域通过广泛的疏水界面（类似于 650 埃 (2)）进行接触，表明它们的相对方向是固定的。因此，Hsc20除了在调节Hsc66的ATP酶活性中发挥作用外，还可以充当刚性支架以促进针对Hsc66的蛋白质底物的定位。 (C) 2000 年学术出版社。
Hsc20 is a 20 kDa T-protein that regulates the ATPase activity and peptide-binding specificity of Hsc66, an hsp70-class molecular chaperone. We report herein the crystal structure of Hsc20 from Escherichia coli determined to a resolution of 1.8 Angstrom using a combination of single isomorphous replacement (SIR) and multi-wavelength anomalous diffraction (MAD). The overall structure of Hsc20 consists of two distinct domains, an N-terminal J-domain containing residues 1-75 connected by a short loop to a C-terminal domain containing residues 84-171. The structure of the J-domain, involved in interactions with Hsc66, resembles the sc-topology of J-domain fragments of Escherichia coli DnaJ and human Hdj1 previously determined by solution NMR methods. The C-terminal domain, implicated in binding and targeting proteins to Hsc66, consists of a three-helix bundle in which two helices comprise an anti-parallel colied-coli. The two domains make contact through an extensive hydrophobic interface (similar to 650 Angstrom (2)) suggesting that their relative orientations are fixed. Thus, Hsc20, in addition to its role in the regulation of the ATPase activity of Hsc66, may also function as a rigid scaffold to facilitate positioning of the protein substrates targeted to Hsc66. (C) 2000 Academic Press.