Solution structure of the HRDC domain of human Bloom syndrome protein BLM.
Solution structure of the HRDC domain of human Bloom syndrome protein BLM.
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DOI：
10.1093/jb/mvq097
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发表时间：
2010-10
影响因子：
2.7
通讯作者：
A. Sato;M. Mishima;A. Nagai;Sun-Yong Kim;Yutaka Ito;T. Hakoshima;J. Jee;K. Kitano
中科院分区：
文献类型：
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作者：
A. Sato;M. Mishima;A. Nagai;Sun-Yong Kim;Yutaka Ito;T. Hakoshima;J. Jee;K. Kitano
布卢姆综合征是一种罕见的遗传性疾病，其特征是严重的生长迟缓和癌症易感性。这种疾病是由Bloom综合征蛋白（BLM）的功能丧失引起的，BLM是DNA解旋酶RecQ家族的成员。在这里，我们报告的第一个3D结构的BLM片段，解决方案的C-末端解旋酶和核糖核酸酶D-C-末端（HRDC）域从人类BLM结构。该结构揭示了BLM HRDC的独特特征，其不同于Werner综合征蛋白的HRDC结构域。特别是，BLM HRDC保留了许多暴露于溶剂的酸性残基，这使得结构域表面广泛地带负电。与此一致，荧光偏振测定显示分离的BLM HRDC无法与DNA底物相互作用。采用超离心、凝胶过滤、CD光谱和动态光散射分析表明，BLM HRDC结构域在溶液中以稳定的单体形式存在。结果表明，BLM HRDC是一个紧凑的，强大的和酸性的基序，它可能发挥独特的作用，除了DNA结合。
Bloom syndrome is a rare genetic disorder characterized by severe growth retardation and cancer predisposition. The disease is caused by a loss of function of the Bloom syndrome protein (BLM), a member of the RecQ family of DNA helicases. Here we report on the first 3D structure of a BLM fragment, a solution structure of the C-terminal helicase-and-ribonuclease D-C-terminal (HRDC) domain from human BLM. The structure reveals unique features of BLM HRDC that are distinct from the HRDC domain of Werner syndrome protein. In particular, BLM HRDC retains many acidic residues exposed to the solvent, which makes the domain surface extensively electronegative. Consistent with this, fluorescence polarization assays showed an inability of isolated BLM HRDC to interact with DNA substrates. Analyses employing ultracentrifugation, gel-filtration, CD spectroscopy and dynamic light scattering showed that the BLM HRDC domain exists as a stable monomer in solution. The results show that BLM HRDC is a compact, robust and acidic motif which may play a distinct role apart from DNA binding.