a-Helix stabilization by co-operative side chain charge-reinforced interactions to phosphoserine in a basic kinase-substrate motif
a-Helix stabilization by co-operative side chain charge-reinforced interactions to phosphoserine in a basic kinase-substrate motif
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通过与碱性激酶底物基序中的磷酸丝氨酸的协同侧链电荷增强相互作用来稳定α螺旋
DOI：
10.1101/2021.11.27.470016
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Batchelor M
中科院分区：
文献类型：
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作者：
Batchelor M
细胞功能是如何通过促进或抑制蛋白质-蛋白质相互作用(PPI)的蛋白质磷酸化事件来调节的，这是理解调控分子机制的关键。虽然磷酸化可以以正构化或变构的方式影响蛋白质识别，但对识别基序构象中磷酸驱动的变化的研究较少。我们最近发现，笼蛋白重链通过一个螺旋基序识别磷酸化的TACC3，而在未磷酸化的蛋白质中，该基序是无序的。然而，目前尚不清楚磷酸化是否以及如何在更广泛的背景下稳定螺旋。在目前的手稿中，我们使用基于聚ALA的模型多肽和一套圆二色谱和核磁共振光谱来解决这一挑战。我们发现，在Arg(Iα3)pSeriLys(I+4)三联体的背景下，丝氨酸残基的磷酸化通过电荷增强的侧链相互作用与正的协同作用稳定了−-螺旋，而苏氨酸的磷酸化则诱导了相反的反应。这一点意义重大，因为它可能代表了通过磷酸化控制PPI的一般方法；基本的激酶底物基序是共同的，55个人类蛋白激酶识别位于−3位的精氨酸与磷酸化的丝氨酸，而精氨酸(I−3)SeriLys(I+4)是在2000多种人类蛋白质中发现的基序。
How cellular functions are regulated through protein phosphorylation events that promote or inhibit protein–protein interactions (PPIs) is key to understanding regulatory molecular mechanisms. Whilst phosphorylation can orthosterically or allosterically influence protein recognition, phospho-driven changes in the conformation of recognition motifs are less well explored. We recently discovered that clathrin heavy chain recognizes phosphorylated TACC3 through a helical motif that, in the unphosphorylated protein, is disordered. However, it was unclear whether and how phosphorylation could stabilize a helix in a broader context. In the current manuscript, we address this challenge using poly-Ala-based model peptides and a suite of circular dichroism and nuclear magnetic resonance spectroscopies. We show that phosphorylation of a Ser residue stabilizes the α-helix in the context of an Arg(i−3)pSeriLys(i+4)triad through charge-reinforced side chain interactions with positive co-operativity, whilst phosphorylation of Thr induces an opposing response. This is significant as it may represent a general method for control of PPIs by phosphorylation; basic kinase-substrate motifs are common with 55 human protein kinases recognizing an Arg at a position −3 from the phosphorylated Ser, whilst the Arg(i−3)SeriLys(i+4)is a motif found in over 2000 human proteins.