Institute of Chemistry, University of Tartu, Estonia.
Bioorg Chem. 2010 Oct;38(5):229-33. doi: 10.1016/j.bioorg.2010.05.004. Epub 2010 Jun 1.
Peptidomimetic analogs of the peptide RRASVA, known as the "minimal substrate" of the catalytic subunit of the cAMP-dependent protein kinase (PKA), were synthesized by consecutive replacement of natural amino acids by their aza-beta(3) analogs. The peptidomimetics were tested as PKA substrates and the kinetic parameters of the phosphorylation reaction were determined. It was found that the interaction of these peptidomimetics with the enzyme active center was sensitive to the location of the backbone modification, while the maximal rate of the reaction was practically not affected by the structure of substrates. The pattern of molecular recognition of peptidomimetics was in agreement with the results of structure modeling and also with the results of computational docking study of peptide and peptidomimetic substrates with the active center of PKA. It was concluded that the specificity determining factors which govern substrate recognition by the enzyme should be grouped along the phosphorylatable substrate, and such clustering might open new perspectives for pharmacophore design of peptides and peptide-like ligands.
RRASVA 肽的肽模拟物，被称为 cAMP 依赖性蛋白激酶（PKA）催化亚基的“最小底物”，是通过连续用其氮杂-β（3）类似物替代天然氨基酸合成的。对肽模拟物进行了 PKA 底物测试，并确定了磷酸化反应的动力学参数。结果发现，这些肽模拟物与酶活性中心的相互作用对骨架修饰的位置敏感，而反应的最大速率实际上不受底物结构的影响。肽模拟物的分子识别模式与结构建模的结果以及与 PKA 活性中心的肽和肽模拟物底物的计算对接研究的结果一致。结论是，决定酶识别底物的特异性因素应该沿着可磷酸化的底物分组，这种聚类可能为肽和类肽配体的药效团设计开辟新的前景。
