Mechanistic insights into phosphoprotein-binding FHA domains.
Mechanistic insights into phosphoprotein-binding FHA domains.
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DOI：
10.1021/ar700148u
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发表时间：
2008-08
影响因子：
18.3
通讯作者：
Van Doren, Steven R.
中科院分区：
文献类型：
--
作者：
Liang, Xiangyang;Van Doren, Steven R.
FHA 结构域是通过监测目标蛋白苏氨酸残基的磷酸化来切换多种生物途径中信号的蛋白质模块。作为深入了解细胞避免癌症的努力的一部分，参与细胞对 DNA 损伤反应的 FHA 结构域已经得到了特别好的表征。 FHA 结构域所在的完整蛋白质和相互作用伙伴决定了信号传导的性质。因此，一个关键的生化问题是：FHA 域如何从细胞中数千个替代品中挑选出它们的伴侣？本帐户讨论了 FHA 结构域的结构、亲和力和特异性及其功能结构的形成。尽管 FHA 结构域仅在五个环残基上共享序列同一性，但它们都折叠成两个 β-折叠的 β-三明治。识别环的保守 Arg 和 Ser 识别目标 Thr 的磷酸化。从连接 β 链 4 与 5、6 与 7、或 10 与 11 的环发出的侧链与配体的氨基酸发生特异性接触，从而定制序列偏好。许多 FHA 结构域选择扩展构象的伴侣，某种程度上根据序列中磷酸化苏氨酸后的三个残基（pT+3 位置）。一组 FHA 结构域选择 pT+3 处的短含羧酸侧链。另一组选择长的支化脂肪族侧链。第三组更喜欢 pT+3 处的其他疏水性或不带电荷的极性侧链。然而，另一个 FHA 域则根据 pT−2、pT−3 和 pT+1 位置进行选择。相反，来自人类癌症标记物的 FHA 结构域选择了一个更长的蛋白质片段，该片段在其 β 折叠上添加了 β 链，并将来自新型螺旋的疏水残基呈现到通常的识别表面。通过生物信息学方法预测了整个 FHA 结构域家族的这种新的识别位点和用于结合其他类型蛋白质伴侣的更远程位点。 FHA 结构域、SH2 结构域和 PTB 结构域的磷酸肽依赖性动力学表明了一个共同的主题：刚性的预制结合表面支持范德华接触，从而提供有利的结合焓。尽管与结合事件相关的 FHA 结构域缺乏明显的构象变化，但更微妙的调整是可能的。在测试的一个 FHA 结构域中，磷酸苏氨酸肽结合伴随着结合位点外部的灵活性增加和整个 β-夹心结构的刚性增加。相同 FHA 结构域的折叠通过近天然中间体进行，这些中间体稳定了磷蛋白结合表面中心的识别环；这可能会促进界面的刚性和对苏氨酸磷酸化靶标的亲和力。
FHA domains are protein modules that switch signals in diverse biological pathways by monitoring the phosphorylation of threonine residues of target proteins. As part of the effort to gain insight into cellular avoidance of cancer, FHA domains involved in the cellular response to DNA damage have been especially well characterized. The complete protein where the FHA domain resides and the interaction partners determine the nature of the signaling. Thus, a key biochemical question is: how do FHA domains pick out their partners from among thousands of alternatives in the cell? This Account discusses the structure, affinity, and specificity of FHA domains and the formation of their functional structure. Although FHA domains share sequence identity at only five loop residues, they all fold into a β-sandwich of two β-sheets. The conserved Arg and Ser of the recognition loops recognize the phosphorylation of the Thr targeted. Side chains emanating from loops that join β-strand 4 with 5, 6 with 7, or 10 with 11 make specific contacts with amino acids of the ligand that tailor sequence preferences. Many FHA domains choose a partner in extended conformation, somewhat according to the residue three after the phosphoThr in sequence (pT+3 position). One group of FHA domains chooses a short carboxylate-containing side chain at pT+3. Another group chooses a long, branched aliphatic side chain. A third group prefers other hydrophobic or uncharged, polar side chains at pT+3. However, another FHA domain instead chooses on the basis of pT−2, pT−3, and pT+1 positions. An FHA domain from a marker of human cancer instead chooses a much longer protein fragment that adds a β-strand to its β-sheet and that presents hydrophobic residues from a novel helix to the usual recognition surface. This novel recognition site and more remote sites for the binding of other types of protein partners were predicted for the entire family of FHA domains by a bioinformatics approach. The phosphopeptide-dependent dynamics of an FHA domain, SH2 domain, and PTB domain suggest a common theme: rigid, preformed binding surfaces support van der Waals contacts that provide favorable binding enthalpy. Despite the lack of pronounced conformational changes in FHA domains linked to binding events, more subtle adjustments may be possible. In the one FHA domain tested, phosphoThr peptide binding is accompanied by increased flexibility just outside the binding site and increased rigidity across the β-sandwich. The folding of the same FHA domain progresses through near-native intermediates that stabilize the recognition loops in the center of the phosphoprotein-binding surface; this may promote rigidity in the interface and affinity for targets phosphorylated on threonine.
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DOI：
10.1073/pnas.2031918100
发表时间：
2003-09-30
影响因子：
11.1
作者：
Lee, GI;Ding, ZF;Van Doren, SR
通讯作者：
Van Doren, SR
影响因子：
5.3
作者：
Pike, BL;Yongkiettrakul, S;Heierhorst, J
通讯作者：
Heierhorst, J
影响因子：
16
作者：
Durocher, D;Taylor, IA;Yaffe, MB
通讯作者：
Yaffe, MB
影响因子：
7.4
作者：
Stone, JM;Trotochaud, AE;Clark, SE
通讯作者：
Clark, SE
影响因子：
56.9
作者：
Sun, ZX;Hsiao, J;Stern, DF
通讯作者：
Stern, DF