Solution structure of the HMG protein NHP6A and its interaction with DNA reveals the structural determinants for non-sequence-specific binding
Solution structure of the HMG protein NHP6A and its interaction with DNA reveals the structural determinants for non-sequence-specific binding
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DOI：
10.1093/emboj/18.9.2563
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发表时间：
1999-05-04
期刊：
影响因子：
11.4
通讯作者：
Feigon, J
中科院分区：
文献类型：
--
作者：
Allain, FHT;Yen, YM;Feigon, J
NHP6A是一种来自非特异性DNA结合蛋白HMG1/2家族的酿酒酵母的染色质相关蛋白。 NHP6A仅具有一个HMG DNA结合结构域，并与DNA形成相对稳定的复合物，我们确定了NHP6A的溶液结构，并构建了DNA复合物的基于NMR的模型结构。自由NHP6A折叠成L形的三个α-螺旋结构，并包含一个非结构化的17氨基酸基本底尾N端，位于HMG盒中。分配的NHP6A和15 bp C-13，N-15标记的DNA双链体之间分配的分子间NOE，其中包含SRY识别序列已将NHP6A HMG结构域定位在DNA的次要凹槽上，该位点的位置偏移了1 bp，并反向逆转和反向移动从SRY-DNA复合物中发现的方向。在NHP6A-DNA复合物的模型结构中，N末端碱性尾巴以模仿LEF1的C末端尾巴的方式包裹在主要的凹槽上，该复合物中的DNA严重变形，并包含两个相邻的Kinks，其中侧面有两个侧面的侧面，侧面侧面侧面的侧面侧面的侧面侧面的DNA。插入对弯曲很重要的蛋氨酸和苯丙氨酸的链。 NHP6A-DNA模型结构提供了有关该类别架构DNA结合蛋白如何选择优先结合位点的洞察力。
NHP6A is a chromatin-associated protein from Saccharomyces cerevisiae belonging to the HMG1/2 family of non-specific DNA binding proteins. NHP6A has only one HMG DNA binding domain and forms relatively stable complexes with DNA, We have determined the solution structure of NHP6A and constructed an NMR-based model structure of the DNA complex. The free NHP6A folds into an L-shaped three alpha-helix structure, and contains an unstructured 17 amino acid basic tail N-terminal to the HMG box. Intermolecular NOEs assigned between NHP6A and a 15 bp C-13,N-15-labeled DNA duplex containing the SRY recognition sequence have positioned the NHP6A HMG domain onto the minor groove of the DNA at a site that is shifted by 1 bp and in reverse orientation from that found in the SRY-DNA complex. In the model structure of the NHP6A-DNA complex, the N-terminal basic tail is wrapped around the major groove in a manner mimicking the C-terminal tail of LEF1, The DNA in the complex is severely distorted and contains two adjacent kinks where side chains of methionine and phenylalanine that are important for bending are inserted. The NHP6A-DNA model structure provides insight into how this class of architectural DNA binding proteins may select preferential binding sites.