Vibrational-exciton couplings for the amide i, II, III, and a modes of peptides
Vibrational-exciton couplings for the amide i, II, III, and a modes of peptides
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DOI：
10.1021/jp070369b
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发表时间：
2007-09-20
影响因子：
3.3
通讯作者：
Mukamel, Shaul
中科院分区：
文献类型：
--
作者：
Hayashi, Tomoyuki;Mukamel, Shaul
计算了所有酰胺基元与其泛频和组合振动态之间的耦合。结合先前报道的能级能量（Hayashi，T.;庄文; Mukamel，S. J.Phys.Chem.A2005，109，9747），我们获得了整个酰胺体系的完整有效振动哈密顿量。在BPW 91/6-3 IG（d，p）水平上，利用甘氨酸二肽（GLDP）的非谐振动哈密顿量，得到了相邻肽单元之间的耦合.非相邻单元间的静电耦合采用四阶跃迁多极耦合（TMC）展开，包括1/R-3（偶极-偶极）、1/R-4 4（四极-偶极）和1/R-5（四极-四极和八极-偶极）相互作用。计算了不同酰胺带的激子离域长度及其随频率的变化。计算得到的24个残基（SPE 3）的酰胺Ⅰ、Ⅱ吸收光谱和圆二色光谱与实验结果符合较好。
The couplings between all amide fundamentals and their overtones and combination vibrational states are calculated. Combined with the level energies reported previously (Hayashi, T.; Zhuang, W.; Mukamel, S. J. Phys. Chem. A 2005, 109, 9747), we obtain a complete effective vibrational Hamiltonian for the entire amide system. Couplings between neighboring peptide units are obtained using the anharmonic vibrational Hamiltonian of glycine dipeptide (GLDP) at the BPW91/6-3 I G(d,p) level. Electrostatic couplings between non-neighboring units are calculated by the fourth rank transition multipole coupling (TMC) expansion, including 1/R-3 (dipole-dipole), 1/R-4 4 (quadrupole-dipole), and 1/R-5 (quadrupole-quadrupole and octapole-dipole) interactions. Exciton delocalization length and its variation with frequency in the various amide bands are calculated. The simulated infrared amide I and II absorptions and CD spectra of 24 residue (x-helical motifs (SPE3) are in good agreement with experiment.