Dependence of tryptophan emission wavelength on conformation in cyclic hexapeptides
Dependence of tryptophan emission wavelength on conformation in cyclic hexapeptides
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DOI：
10.1021/jp056164p
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发表时间：
2006-04-06
影响因子：
3.3
通讯作者：
Barkley, MD
中科院分区：
文献类型：
--
作者：
Pan, CP;Callis, PR;Barkley, MD
色氨酸的最大发射波长取决于吲哚生色团的局部静电环境。测定了7个含单一色氨酸残基的刚性环六肽的时间分辨发射光谱。这7个多肽的三个衰变相关光谱的最大发射波长在341~359 nm之间，表明不同的色氨酸旋转异构体即使在溶剂暴露的情况下也有不同的发射极大值。这一结论得到了对溶剂化六肽中色氨酸的六个典型侧链旋转体的量子力学/分子动力学模拟的支持。计算得到7种多肽的色氨酸旋转体的最大发射波长范围为344-365 nm。考察了波长计算的精确度以及多肽、水和带电侧链对光谱位移的贡献。结果表明，衰变相关光谱的发射极大值有助于指定色氨酸旋转体的荧光寿命。
The wavelength of maximum emission of tryptophan depends on the local electrostatic environment of the indole chromophore. The time-resolved emission spectra of seven rigid cyclic hexapeptides containing a single tryptophan residue were measured. The emission maxima of the three decay-associated spectra for the seven peptides ranged from 341 to 359 nm, suggesting that different tryptophan rotamers have different emission maxima even in the case of solvent-exposed tryptophans. This conclusion is Supported by quantum mechanical/ molecular dynamics simulations of the six canonical side chain rotarners of tryptophan in solvated hexapeptides. The calculated range of emission maxima for the tryptophan rotamers of the seven peptides is 344-365 nm. The precision of the wavelength calculations and the peptide, water, and charged side chain contributions to the spectral shifts are examined. The results indicate that the emission maxima of decay-associated spectra call aid in the assignment of fluorescence lifetimes to tryptophan rotamers.