Fourier transform vibrational circular dichroism as a decisive tool for conformational studies of peptides containing tyrosyl residues
Fourier transform vibrational circular dichroism as a decisive tool for conformational studies of peptides containing tyrosyl residues
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DOI：
10.1002/bip.10247
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发表时间：
2003-01-01
期刊：
影响因子：
2.9
通讯作者：
Lovas, S
中科院分区：
文献类型：
--
作者：
Borics, A;Murphy, RF;Lovas, S
先前的UV-圆二色性（UV-CD）和NMR研究表明，Ac-AAAAAAAAAEAAKA-NH 2在50%（v/v）三氟乙醇水溶液中具有α-螺旋结构。用Tyr将Ala（1）替换为Ala（6）导致光谱显示在相同溶剂中螺旋度的明显损失。这种螺旋度的明显损失可归因于酪氨酰侧链发色团与骨架酰胺的偶联。然而，这样的电子耦合不影响振动CD（VCD）光谱。含有酪氨酰残基的肽的VCD光谱与不含Tyr的肽的VCD光谱相同，其显示相同的α-螺旋结构。因为现在很清楚Tyr取代不会改变肽的骨架构象，所以当电子效应可能干扰固有结构的UV-CD光谱时，UV-CD测量应通过VCD补充以确定二级结构。(C)2002 Wiley Periodicals，Inc.
Previous UV-circular dichroism (UV-CD) and NMR studies showed that Ac-AAAAAAAEAAKA-NH2 has an alpha-helical structure in 50% (v/v) aqueous trifluoroethanol. Replacement of Ala(1) to Ala(6) with Tyr results in spectra that show an apparent loss of helicity in the same solvent. This apparent loss of helicity could be attributed to the coupling of the tyrosyl side chain chromophore with the backbone amide. However, such electronic coupling does not affect the vibrational CD (VCD) spectra. The VCD spectra of the peptides with tyrosyl residues were identical to that of the peptide containing no Tyr, which shows the same a-helical structure. Because it is now clear that Tyr replacement does not change the backbone conformation of peptides, UV-CD measurements should be complemented by VCD to determine the secondary structure when electronic effects can disturb the UV-CD spectrum of the inherent structure. (C) 2002 Wiley Periodicals, Inc.