甘氨酸色氨酸寡肽链的红外光谱的密度泛函研究

运用密度泛函理论, 在6-31 G(d) 基组水平上对甘氨酸色氨酸交替组成的六种寡肽链结构进行几何优化, 并进行了结合能和振动光谱地分析. 结果表明, 寡肽的生长利于结构的稳定性. 随着肽链的生长, 单一基团的振动存在蓝移或奇偶震荡现象; 同类官能团的耦合振动存在红移现象; 而肽链端部基团的振动频率基本不变. 这些丰富的频移现象和尺寸效应、耦合效应、诱导效应、奇偶效应等因素共同竞争有关. 该结果对应用红外光谱对寡肽链的残基数及长度地测量等工作有指导意义. 关键词： 寡肽链 红外光谱 耦合效应 尺寸效应

DFT research on the IR spectrum of glycine tryptophan oligopeptides chain

By using the density functional theory, six structures of oligopeptides chain configuration, consisting of glycine and tryptophan alternatively, are optimized at the B3LYP/6-31 G(d) level. The average binding energy and IR spectrum are calculated. Results show that the stability of oligopeptides grows monotonously with the peptide chain growth. The vibration infrared spectrum analysis show that with the growth of oligopeptides peptide chain, the vibration frequency of one functional group shows blue shift or even-odd shift; while coupling vibration of the same functional group shows red shift, and steady frequencies at the end of chain appear on the infrared spectrum, that is to say, coupling effect, parity effect and size effect exist when, glycine tryptophan oligopeptides, consisting of glycine and tryptophan alternatively, change with peptide chain. The result is significant in measuring the length and number of residue of peptide chain.
Keywords： oligopeptides infrared spectrum coupling effect size effect