Rodríguez M, Benito A, Tubert P, Castro J, Ribó M, Beaumelle B, Vilanova M
Laboratori d'Enginyeria de Proteïnes, Departament de Biologia, Facultat de Ciències, Universitat de Girona, Campus de Montilivi, 17071 Girona, Spain.
J Mol Biol. 2006 Jul 14;360(3):548-57. doi: 10.1016/j.jmb.2006.05.048. Epub 2006 Jun 5.
Nuclear import of proteins is determined by specific signals that allow them to bind to receptors that mediate their energy-dependent transport through the nuclear pore. These signals are termed nuclear localization signals and do not constitute a specific consensus sequence. Among them, the most characterized correspond to monopartite and bipartite nuclear localization signals, which interact with the importin alpha/beta heterodimer. We previously described a cytotoxic variant of human pancreatic-ribonuclease that is actively transported into the nucleus. Here, we show that this protein interacts with importin alpha through different basic residues, including Lys1 and the arginine clusters 31-33 and 89-91. Although these residues are scattered along the sequence, they are close in the three-dimensional structure of the protein and their topological disposition strongly resembles that of a classical bipartite nuclear localization signal.
蛋白质的核输入由特定信号决定，这些信号使它们能够与受体结合，介导其通过核孔的能量依赖性转运。这些信号被称为核定位信号，并不构成特定的共有序列。其中，最具特征的对应于单部分和双部分核定位信号，它们与输入蛋白α/β异二聚体相互作用。我们之前描述了一种人胰腺核糖核酸酶的细胞毒性变体，它能被主动转运到细胞核中。在这里，我们表明该蛋白通过不同的碱性残基与输入蛋白α相互作用，包括赖氨酸1以及精氨酸簇31 - 33和89 - 91。尽管这些残基沿序列分散，但在蛋白质的三维结构中它们彼此靠近，并且它们的拓扑排列与经典的双部分核定位信号非常相似。
