Ruzza Paolo, Calderan Andrea, Donella-Deana Arianna, Biondi Barbara, Cesaro Luca, Osler Alessio, Elardo Stefano, Guiotto Andrea, Pinna Lorenzo A, Borin Gianfranco
Institute of Biomolecular Chemistry, Padova Unit, CNR, via Marzolo 1, 35131 Padua, Italy.
Biopolymers. 2003;71(4):478-88. doi: 10.1002/bip.10469.
The side-chain orientation of a tyrosine residue located in a peptide, which is an excellent substrate of Syk tyrosine kinase (A. M. Brunati, A. Donella-Deana, M. Ruzzene, O. Marin, L. A. Pinna, FEBS Letters, 1995, Vol. 367, pp. 149-152), was fixed in the gauche (+) or gauche (-) conformation by using the 7-hydroxy-1,2,3,4-tetrahydro isoquinoline-3-carboxylic (Htc) structure. The tyrosine trans conformation was blocked by using an aminobenzazepine-type (Hba) structure. The proposed side-chain orientations were confirmed by the analysis of the (1)H-NMR parameters: chemical shifts, coupling constants, and nuclear Overhauser effects to the tyrosine constraints in the different analogs. This "rotamer scan" of the phosphorylatable residue allowed us to generate optimal substrates in terms of both phosphorylation efficiency and selectivity for Syk tyrosine kinase. In contrast, these conformationally restricted tyrosine analogs were not tolerated by the Src-related tyrosine kinases Lyn and c-Fgr.
位于一种肽中的酪氨酸残基的侧链取向，该肽是Syk酪氨酸激酶的优良底物（A.M.布鲁纳蒂、A.多内拉 - 迪阿纳、M.鲁泽内、O.马林、L.A.皮纳，《欧洲生物化学学会联合会快报》，1995年，第367卷，第149 - 152页），通过使用7 - 羟基 - 1,2,3,4 - 四氢异喹啉 - 3 - 羧酸（Htc）结构固定在gauche（+）或gauche（-）构象中。酪氨酸反式构象通过使用氨基苯并氮杂䓬型（Hba）结构被阻断。通过对（1）H - NMR参数的分析证实了所提出的侧链取向：化学位移、耦合常数以及对不同类似物中酪氨酸约束的核Overhauser效应。这种可磷酸化残基的“旋转异构体扫描”使我们能够在磷酸化效率和对Syk酪氨酸激酶的选择性方面生成最佳底物。相比之下，这些构象受限的酪氨酸类似物不被Src相关的酪氨酸激酶Lyn和c - Fgr所耐受。
