High-resolution NMR studies of structure and dynamics of human ERp27 indicate extensive interdomain flexibility.
High-resolution NMR studies of structure and dynamics of human ERp27 indicate extensive interdomain flexibility.
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DOI：
10.1042/bj20121635
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发表时间：
2013-03-01
期刊：
影响因子：
--
通讯作者：
Freedman RB
中科院分区：
文献类型：
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作者：
Amin NT;Wallis AK;Wells SA;Rowe ML;Williamson RA;Howard MJ;Freedman RB
ERp 27（内质网蛋白27.7 kDa）是位于内质网的PDI（蛋白质二硫键异构酶）的同源物。预测ERp 27由与PDI的非催化B和B′结构域同源的两个硫氧还蛋白折叠结构域组成。使用高分辨率NMR数据解析ERp 27的N-末端b样结构域的溶液中的结构。结构证实它具有硫氧还蛋白折叠，并且ERp 27是PDI家族的成员。获得了15 N-NMR弛豫数据，ModelFree分析强调了有限的交换贡献和缓慢的内部运动，并表明该结构域的平均有序参数S2为0.79。在本研究中确定的单域结构与全长ERp 27内的等效域的比较，通过X射线衍射独立确定，表明非常接近的协议。从溶液中的NMR数据推断的域接口比在X-射线结构中观察到的要广泛得多，这表明域独立地弯曲，结晶选择一个特定的域间取向。这使我们应用一种新的快速方法来模拟全长蛋白质的灵活性，建立结构域显示出相当大的自由度来弯曲（倾斜和扭曲）域间连接体，与NMR数据一致。
ERp27 (endoplasmic reticulum protein 27.7 kDa) is a homologue of PDI (protein disulfide-isomerase) localized to the endoplasmic reticulum. ERp27 is predicted to consist of two thioredoxin-fold domains homologous with the non-catalytic b and b′ domains of PDI. The structure in solution of the N-terminal b-like domain of ERp27 was solved using high-resolution NMR data. The structure confirms that it has the thioredoxin fold and that ERp27 is a member of the PDI family. 15N-NMR relaxation data were obtained and ModelFree analysis highlighted limited exchange contributions and slow internal motions, and indicated that the domain has an average order parameter S2 of 0.79. Comparison of the single-domain structure determined in the present study with the equivalent domain within full-length ERp27, determined independently by X-ray diffraction, indicated very close agreement. The domain interface inferred from NMR data in solution was much more extensive than that observed in the X-ray structure, suggesting that the domains flex independently and that crystallization selects one specific interdomain orientation. This led us to apply a new rapid method to simulate the flexibility of the full-length protein, establishing that the domains show considerable freedom to flex (tilt and twist) about the interdomain linker, consistent with the NMR data.