Aspartate Embedding Depth Affects pHLIP's Insertion pKa
Aspartate Embedding Depth Affects pHLIP's Insertion pKa
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DOI：
10.1021/bi400252k
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发表时间：
2013-07-09
期刊：
影响因子：
2.9
通讯作者：
Engelman, Donald M.
中科院分区：
文献类型：
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作者：
Fendos, Justin;Barrera, Francisco N.;Engelman, Donald M.
我们利用pH低插入多肽(PHLIP)家族研究了天冬氨酸嵌入深度在pH依赖的跨膜多肽插入中的作用。在中性pH条件下，Phlip主要以非结构化单体的形式结合到脂质双层的表面。当pH降低时，当pH调节回到中性值时，作为跨越α-螺旋的PHLIP插入是可逆的，pH LIP自发地插入跨膜。促进PHLIP插入的关键事件之一是肽跨结构域中天冬氨酸的质子化，这些残基的负侧链转化为不带电荷的极性形式，有助于插入改变跨结构域的疏水性。为了进一步研究这种质子化机制，我们创建了PHLIP序列，其中两个跨越天冬氨酸(D14和D25)在序列中向上或向下移动。我们假设插入状态下的天冬氨酸深度将直接影响酸性侧链的质子亲和力，改变pH依赖的插入的pK(A)。为此，我们还对精氨酸的位置进行了突变。11为了确定精氨酸浮潜是否通过影响天冬氨酸深度来调节插入PK(A)，我们的结果表明两种类型的突变都改变了插入PK(A)，支持了天冬氨酸深度的观点。决定pH依赖性的参与参数。我们还表明，PHLIP对聚集的抵抗力可以随着我们的突变而改变，从而确定了一种新的标准，用于提高PHLIP在体内针对癌症和炎症等酸性疾病组织的性能。
We have used the pH low insertion peptide (pHLIP) family to study the role of aspartate embedding depth in pH-dependent transmembrane peptide insertion.. pHLIP binds to the surface of a lipid bilayer as a largely unstructured monomer at neutral pH. When the pH is lowered, pH LIP inserts spontaneously across the membrane as a spanning alpha-helix pHLIP insertion is reversible when the pH is adjusted back to a neutral value. One of the critical events facilitating pHLIP insertion is the protonation of aspartates in the spanning domain of the peptide the negative side chains of these residues convert to uncharged polar forms, facilitating insertion altering the hydrophobicity of the spanning domain. To examine this protonation Mechanism further we created, pHLIP sequence, variants in which the two spanning aspartates (D14 and D25) were moved up or down in the sequence. We hypothesized that the aspartate depth in the inserted state would directly affect the proton affinity of the acidic side chains, altering the pK(a) of pH-dependent insertion. To this end, we also mutated the arginine at position. 11 to determine whether arginine snorkeling modulates the insertion pK(a) by affecting the aspartate depth our results indicate that both types of Mutations-change the insertion pK(a), supporting the idea that the aspartate depth. Participating parameter in determining the pH dependence. We also show that pHLIP's resistance to aggregation can be altered with our mutations, identifying a new criterion for improving the performance of pHLIP in Vivo when targeting acidic disease tissues such as cancer and inflammation.