Darwish Marie A, Veggerby C, Robertson D H, Gaskell S J, Hubbard S J, Martinsen L, Hurst J L, Beynon R J
Department of Veterinary Preclinical Sciences, University of Liverpool, Liverpool, L69 3BX, United Kingdom.
Protein Sci. 2001 Feb;10(2):411-7. doi: 10.1110/ps.31701.
Mouse urine contains an abundance of major urinary proteins, lipocalins, whose roles include slow release of semiochemicals. These proteins are highly polymorphic, with small sequence differences between individual members. In this study, we purified to homogeneity four of these proteins from two strains of inbred mice and characterized them by mass spectrometry. This analysis has led to the discovery of another variant in this group of proteins. Three of the polymorphic variants that map to the surface have no effect on the binding of a fluorescent probe in the binding cavity, but the fourth, characterized by a Phe to Val substitution in the cavity, shows a substantially lower affinity and fluorescence yield for the probe. These results are interpreted in light of the known crystal structure of the protein and molecular modeling calculations, which rationalize the experimental findings. This work raises the possibility that the calyx-binding site can show specificity for different ligands, the implications of which on pheromone binding and chemical communication are discussed.
小鼠尿液中含有大量主要尿蛋白，即脂质运载蛋白，其作用包括信息素的缓慢释放。这些蛋白质具有高度多态性，个体成员之间的序列差异很小。在本研究中，我们从两个近交系小鼠品系中纯化出四种此类蛋白质并使其达到均一状态，然后通过质谱对其进行表征。该分析导致在这组蛋白质中发现了另一种变体。定位于表面的三个多态变体对结合腔中荧光探针的结合没有影响，但第四个变体在腔内以苯丙氨酸到缬氨酸的取代为特征，对探针的亲和力和荧光产率显著降低。根据已知的蛋白质晶体结构和分子建模计算对这些结果进行了解释，这些计算使实验结果合理化。这项工作提出了花萼结合位点可能对不同配体具有特异性的可能性，并讨论了其对信息素结合和化学通讯的影响。
