Asplund M C, Zanni M T, Hochstrasser R M
Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
Proc Natl Acad Sci U S A. 2000 Jul 18;97(15):8219-24. doi: 10.1073/pnas.140227997.
Two-dimensional infrared spectra of peptides are introduced that are the direct analogues of two- and three-pulse multiple quantum NMR. Phase matching and heterodyning are used to isolate the phase and amplitudes of the electric fields of vibrational photon echoes as a function of multiple pulse delays. Structural information is made available on the time scale of a few picoseconds. Line narrowed spectra of acyl-proline-NH(2) and cross peaks implying the coupling between its amide-I modes are obtained, as are the phases of the various contributions to the signals. Solvent-sensitive structural differences are seen for the dipeptide. The methods show great promise to measure structure changes in biology on a wide range of time scales.
介绍了肽的二维红外光谱，它是二脉冲和三脉冲多量子核磁共振的直接类似物。利用相位匹配和外差法来分离振动光子回波电场的相位和幅度，作为多脉冲延迟的函数。在几皮秒的时间尺度上可获得结构信息。得到了酰基脯氨酸-NH(2)的线窄光谱以及暗示其酰胺-I模式之间耦合的交叉峰，还有信号各贡献部分的相位。对于二肽观察到了溶剂敏感的结构差异。这些方法在测量广泛时间尺度上生物学中的结构变化方面显示出巨大潜力。
