The method to evaluate the dihedral angles of a polypeptide using IR absorption spectroscopy was applied to a polyproline type II (PPII) structure. We have prepared ¹PPPPPPG⁷-NH₂ with the two successive residues labeled by ¹³C=¹⁸O. The doublet of the ¹³C=¹⁸O stretching band due to the two successive labeled residues was observed, which comes from the vibrational coupling between the labeled residues. The differences in the peak wavenumber and the intensity of the doublet band were analyzed using the GF matrix method and ab initio calculations. The obtained dihedral angles of the labeled residues were compared with the reported values.

中文翻译：

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连续两个同位素标记的残基的红外光谱在聚脯氨酸II结构二面角评估中的应用

使用IR吸收光谱法评价多肽的二面角的方法被应用于II型聚脯氨酸（PPII）结构。我们已经准备¹ PPPPPPG ⁷ -NH ₂用由标为两个连续的残基¹³ C = ¹⁸ O的的双峰¹³ C = ¹⁸，观察到O伸缩带由于两个连续的标记的残基，其来自之间的振动耦合标记的残基。使用GF矩阵法和从头算分析峰波数和双峰带强度的差异。计算。将获得的标记残基的二面角与报告值进行比较。