Erlach Markus Beck, Koehler Joerg, Crusca Edson, Kremer Werner, Munte Claudia E, Kalbitzer Hans Robert
Institute of Biophysics and Physical Biochemistry and Centre of Magnetic Resonance in Chemistry and Biomedicine, University of Regensburg, 93040, Regensburg, Germany.
Physics Institute of São Carlos, University of São Paulo, São Carlos, 13566-590, Brazil.
J Biomol NMR. 2016 Jun;65(2):65-77. doi: 10.1007/s10858-016-0030-4. Epub 2016 Jun 22.
For a better understanding of nuclear magnetic resonance (NMR) detected pressure responses of folded as well as unstructured proteins the availability of data from well-defined model systems are indispensable. In this work we report the pressure dependence of chemical shifts of the backbone atoms (1)H(α), (13)C(α) and (13)C' in the protected tetrapeptides Ac-Gly-Gly-Xxx-Ala-NH2 (Xxx one of the 20 canonical amino acids). Contrary to expectation the chemical shifts of these nuclei have a nonlinear dependence on pressure in the range from 0.1 to 200 MPa. The polynomial pressure coefficients B 1 and B 2 are dependent on the type of amino acid studied. The coefficients of a given nucleus show significant linear correlations suggesting that the NMR observable pressure effects in the different amino acids have at least partly the same physical cause. In line with this observation the magnitude of the second order coefficients of nuclei being direct neighbors in the chemical structure are also weakly correlated.
为了更好地理解核磁共振（NMR）检测到的折叠及非结构化蛋白质的压力响应，来自定义明确的模型系统的数据是必不可少的。在这项工作中，我们报告了受保护的四肽Ac-Gly-Gly-Xxx-Ala-NH2（Xxx为20种标准氨基酸之一）中主链原子（1）H(α)、（13）C(α)和（13）C'的化学位移与压力的关系。与预期相反，这些原子核的化学位移在0.1至200MPa范围内对压力呈非线性依赖关系。多项式压力系数B1和B2取决于所研究的氨基酸类型。给定原子核的系数显示出显著的线性相关性，这表明不同氨基酸中NMR可观测到的压力效应至少部分具有相同的物理原因。与此观察结果一致，化学结构中直接相邻的原子核的二阶系数大小也存在弱相关性。
