Crystal structure of the human centromere protein B (CENP-B) dimerization domain at 1.65-Å resolution
Crystal structure of the human centromere protein B (CENP-B) dimerization domain at 1.65-Å resolution
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DOI：
10.1074/jbc.m310388200
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发表时间：
2003-12-19
影响因子：
4.8
通讯作者：
Yokoyama, S
中科院分区：
文献类型：
--
作者：
Tawaramoto, MS;Park, SY;Yokoyama, S
人着丝粒蛋白B（CENP-B）是一种着丝粒异染色质组分，形成特异性结合不同DNA序列（CENP-B盒）的同源二聚体，该DNA序列出现在每隔一个α-卫星重复序列中。先前，我们确定了与CENP-B盒DNA复合的人CENP-B DNA结合结构域CENP-B-（1-129）的结构。在本研究中，我们以1.65埃的分辨率确定了其二聚化结构域（CENP-B-（540-599））的晶体结构，CENP-B的另一个功能结构域。CENP- B-（540-599）含有两个折叠成反平行构型的α-螺旋。CENP-B-（540-599）二聚体形成一个对称的、反平行的、四螺旋束结构，具有一个大的疏水补丁，其中一个单体的23个残基形成货车德瓦尔斯形式与另一个单体接触。在CENP- B-（540-599）二聚体中，CENP-B-（540-599）的N-末端在二聚体的相对侧上取向。这种CENP- B二聚体构型可能适合于在着丝粒异染色质形成期间捕获两个远距离的CENP-B盒。
The human centromere protein B (CENP-B), a centromeric heterochromatin component, forms a homodimer that specifically binds to a distinct DNA sequence (the CENP-B box), which appears within every other alpha-satellite repeat. Previously, we determined the structure of the human CENP-B DNA-binding domain, CENP-B-(1-129), complexed with the CENP-B box DNA. In the present study, we determined the crystal structure of its dimerization domain (CENP-B-(540-599)), another functional domain of CENP-B, at 1.65-Angstrom resolution. CENP- B-(540-599) contains two alpha-helices, which are folded into an antiparallel configuration. The CENP-B-(540-599) dimer formed a symmetrical, antiparallel, four-helix bundle structure with a large hydrophobic patch in which 23 residues of one monomer form van der Waals contacts with the other monomer. In the CENP- B-(540-599) dimer, the N-terminal ends of CENP-B-(540-599) are oriented on opposite sides of the dimer. This CENP- B dimer configuration may be suitable for capturing two distant CENP-B boxes during centromeric heterochromatin formation.