Probing protein structure and dynamics with resonance Raman spectroscopy: cytochrome c peroxidase and hemoglobin.
Probing protein structure and dynamics with resonance Raman spectroscopy: cytochrome c peroxidase and hemoglobin.
复制标题
利用共振拉曼光谱探测蛋白质结构和动力学：细胞色素 C 过氧化物酶和血红蛋白。
作者：
Spiro,TG;Smulevich,G;Su,C
当激光波长与电子跃迁的波长相匹配时，就会发生共振。由于电子-电子和核运动之间的耦合，某些振动模式被增强，这些模式模拟了分子在共振激发态中的扭曲（Spiro & Stein, 1977）。例如，与-*跃迁的共振增强了发色团7r键被拉伸的模式，而与金属配合物中配体-金属电荷转移跃迁的共振增强了金属-配体键被拉伸的模式。这种增强的选择性意味着RR光谱可以用作复杂生物系统中显色位点的探针。血红素、叶绿素、黄素、视黄醛辅助因子和细菌视紫红质，以及各种铁和铜金属蛋白位点都是已被红外光谱检测过的生物发色团（Spiro, 1988）。最近，由于实用紫外激光源的出现，该技术已扩展到芳香蛋白残基（Hudson & Mayne, 1988）和核酸的嘌呤和嘧啶碱基（Tsubaki等，1988）（Ziegler & Hudson, 1983； Asher等，1983；Fodor等，1986；Jones等，1987）。当然，选择性增强也意味着信息的丢失，因为许多分子感兴趣的位点是非发色团的，尽管它们有时可以被标记为外部发色团（Carey, 1988）。用激光波长处于光谱透明区域的非共振拉曼光谱可以得到完整的振动光谱，也可以用红外光谱得到完整的振动光谱。本研究由NIH GrantGM33576资助。*普林斯顿大学。
Resonance occurs when the laser wavelength matches that of an electronic transition. Because of coupling betweenelec-tronic and nuclear motions, certain vibrational modes are enhanced, those which mimic the distortion of the molecule in its resonant excited state (Spiro & Stein, 1977). For ex-ample, resonance with-* transitions enhances modes in which 7r bonds of the chromophore are stretched, while reso-nance with ligand-metal charge-transfer transitions in metal complexes enhances modes in which the metal-ligand bonds are stretched. This selectivity in the enhancement means that RR spectroscopy can be used as a probe for chromophoric sites in complex biological systems. Hemes, chlorophyll, flavins, the retinylidene cofactor of visual pigments and bacterio-rhodopsin, and a variety of ironand copper metalloprotein sites are among the biological chromophores that have been ex-amined by RR spectroscopy (Spiro, 1988). Recently the technique has been extended to aromatic protein residues (Hudson & Mayne, 1988) and to the purine and pyrimidine bases of nucleic acids (Tsubaki et al., 1988), thanks to the advent of practical UV laser sources (Ziegler & Hudson, 1983; Asher et al., 1983; Fodor et al., 1986; Jones et al., 1987). Of course, selective enhancement also means a loss of information since many sites of molecular interest are non-chromophoric, although they can sometimes be labeled with extrinsic chromophores (Carey, 1988). Completevibrational spectra can be obtained with nonresonance Raman spectroscopy, in which the laser wavelength is in a transparent region of the spectrum, or with infrared spectroscopy. The complete tThis work was supported by NIH GrantGM33576.* Princeton University.