Bour P, Záruba K, Urbanová M, Setnicka V, Matejka P, Fiedler Z, Král V, Volka K
Department of Analytical Chemistry, Institute of Chemical Technology, Prague, Czech Republic.
Chirality. 2000 May;12(4):191-8. doi: 10.1002/(SICI)1520-636X(2000)12:4<191::AID-CHIR5>3.0.CO;2-W.
The Raman and absorption spectra of tetraphenylporphyrin (TPP) were calculated and compared to experiment. The computation was based on the harmonic molecular force field and electric tensors obtained ab initio at the BPW91/6-31G* level. Good agreement was found between experimental and calculated frequencies and intensities. In order to estimate whether induced optical activity in chiral complexes interferes with the signal of peptide vibrations, the vibrational circular dichroism (VCD) spectra of TPP were simulated. The magnetic field perturbation theory (MFP) and the gauge-invariant atomic orbitals (GIAO) were used for the simulation. Such spectra were compared to theoretical VCD intensities of a model tripeptide as well to experimental spectra of a complex of the peptide and tetrakis(p-sulfonatophenyl)porphyrin (TSPP). No significant contribution to VCD signal from the TPP residue was found in experimental spectra. Thus, possible peptide conformational changes occurring during the complexation can be monitored directly in the amide I frequency region.
计算了四苯基卟啉（TPP）的拉曼光谱和吸收光谱，并与实验结果进行了比较。计算基于在BPW91/6 - 31G*水平从头算得到的分子简正力场和电张量。实验频率和强度与计算结果之间吻合良好。为了评估手性配合物中的诱导光学活性是否会干扰肽振动信号，模拟了TPP的振动圆二色性（VCD）光谱。模拟采用了磁场微扰理论（MFP）和规范不变原子轨道（GIAO）。将此类光谱与模型三肽的理论VCD强度以及该肽与四（对磺酸钠苯基）卟啉（TSPP）配合物的实验光谱进行了比较。在实验光谱中未发现TPP残基对VCD信号有显著贡献。因此，在配合过程中可能发生的肽构象变化可以直接在酰胺I频率区域进行监测。
