Krüse J, Noort M, Platenkamp R J, Visser A J
Biochim Biophys Acta. 1981 Mar 27;668(1):35-45. doi: 10.1016/0005-2795(81)90146-x.
Phosphorescence spectra of the tryptophan residues in cowpea chlorotic mottle virus were recorded at 77 K and the influence of the quaternary structure on the emission characteristics was investigated. The position of the phosphorescence maxima appeared to be invariant under changes in the aggregation state of the virus particle. In contrast to the results of fluorescence experiments, the phosphorescence probably originates from tryptophan residues, buried in the hydrophobic interior of the virus. Optical detection of magnetic resonance on the triplet state of the tryptophan residues at 1.2 K shows a slight shift in the zero-field transitions, when the interaction between the protein and the RNA is abolished. This shift is discussed in relation with changes in polarity and in polarizability of the environment of the phosphorescing tryptophan residues when the interaction between RNA and the protein subunits decreases. The zero-field transitions in the virus are further characterized by a large linewidth, when comparisons are made with similar transitions observed in other proteins. This shows great heterogeneity in the environment of tryptophan residues, and makes the recognition and interpretation of changes in the transitions very complicated.
在77K下记录了豇豆花叶病毒中色氨酸残基的磷光光谱，并研究了四级结构对发射特性的影响。磷光最大值的位置在病毒颗粒聚集状态变化时似乎不变。与荧光实验结果相反，磷光可能起源于埋藏在病毒疏水内部的色氨酸残基。在1.2K下对色氨酸残基三重态进行磁共振的光学检测表明，当蛋白质与RNA之间的相互作用被消除时，零场跃迁会有轻微的位移。当RNA与蛋白质亚基之间的相互作用减弱时，这种位移与磷光色氨酸残基环境的极性和极化率变化有关。与在其他蛋白质中观察到的类似跃迁相比，病毒中的零场跃迁还具有较大的线宽。这表明色氨酸残基的环境存在很大的异质性，使得跃迁变化的识别和解释非常复杂。
