The long acidic tail of high mobility group box 1 (HMGB1) protein forms an extended and flexible structure that interacts with specific residues within and between the HMG boxes
The long acidic tail of high mobility group box 1 (HMGB1) protein forms an extended and flexible structure that interacts with specific residues within and between the HMG boxes
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DOI：
10.1021/bi049364k
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发表时间：
2004-09-28
期刊：
影响因子：
2.9
通讯作者：
Musco, G
中科院分区：
文献类型：
--
作者：
Knapp, S;Müller, S;Musco, G
HMGB 1（高迁移率组 B1）是一种保守的染色体蛋白，由两个相似的 DNA 结合域（HMG 框 A 和框 B）组成，通过短碱性延伸段与 30 个残基的酸性 C 末端尾部连接。酸性尾调节 HMGB 1 的 DNA 结合特性，其长度区分不同的 HMGB 家族成员。我们合成了与 HMGB1 中的酸性尾相对应的肽（T 肽），并研究了其与单盒以及与无尾 HMGB1 相对应的片段（指定为 AB(bt) 片段）的结合。 CD 光谱表明 T 肽显着稳定 AB(bt) 片段，并且该复合物具有与全长 HMGB1 相同的热稳定性。量热和 NMR 数据显示，T 肽以 9 muM 的解离常数与框 A 结合，与框 B 的结合更弱。全长 HMGB1 和 AB(bt) 片段的 H-1-N-15 HSQC 谱非常相似；存在的小化学位移差异对应于受添加 T 肽影响的 AB(bt) 片段的残基。我们得出的结论是，T 肽与酸性尾非常相似，并且碱性尾部和酸性尾形成延伸且灵活的片段。尾巴与盒子中的特定残基相互作用，并保护它们免受其他相互作用。
HMGB 1 (high mobility group B1) is a conserved chromosomal protein composed of two similar DNA binding domains (HMG box A and box B) linked by a short basic stretch to an acidic C-terminal tail of 30 residues. The acidic tail modulates the DNA binding properties of HMGB 1, and its length differentiates the various HMGB family members. We synthesized a peptide that corresponds to the acidic tail in HMGB1 (T-peptide) and studied its binding to the single boxes and to the fragment corresponding to tailless HMGB1 (designated as AB(bt) fragment). CD spectroscopy showed that T-peptide stabilizes significantly the AB(bt) fragment and that the complex has an identical thermal stability as full-length HMGB1. Calorimetric and NMR data showed that T-peptide binds with a dissociation constant of 9 muM to box A and much more weakly to box B. H-1-N-15 HSQC spectra of full-length HMGB1 and of the AB(bt) fragment are very similar; the small chemical shift differences that exist correspond to those residues of the AB(bt) fragment that were affected by the addition of the T-peptide. We conclude that the T-peptide mimics closely the acidic tail and that the basic stretch and the acidic tail form an extended and flexible segment. The tail interacts with specific residues in the boxes and shields them from other interactions.