Structural characterization of the HIV-1 Vpr N terminus -: Evidence of cis/trans-proline isomerism
Structural characterization of the HIV-1 Vpr N terminus -: Evidence of cis/trans-proline isomerism
复制标题
DOI：
10.1074/jbc.m305413200
复制
发表时间：
2003-10-31
影响因子：
4.8
通讯作者：
Schubert, U
中科院分区：
文献类型：
--
作者：
Bruns, K;Fossen, T;Schubert, U
96个残基的人类免疫缺陷病毒（HIV）辅助蛋白Vpr在逆转录病毒生命周期中具有多种功能，包括增强病毒在非分裂宿主细胞中的复制、诱导G（2）细胞周期停滞和调节HIV诱导的细胞凋亡。使用动态光散射，圆二色性，和NMR光谱的N末端的Vpr的组合被证明是一个独特的结构域的分子，其行为不同的C-末端结构域的自缔合和二级结构折叠。有趣的是，在N末端的四个高度保守的脯氨酸残基被预测具有高的顺式/反式异构倾向。因此，已经研究了合成的N-末端肽（Vpr（1-40））及其较小片段的高分辨率结构和折叠。1H-1 NMR数据表明Vpr（1-40）在残基17-32之间具有螺旋结构，并且首次在没有任何洗涤剂补充剂的水溶液中观察到这种由脯氨酸残基结合的螺旋。此外，NMR数据显示，所有的脯氨酸残基进行顺式/反式异构体的程度，类似于40%的所有Vpr分子拥有至少一个脯氨酸在顺式构象。这种顺式/反式异构现象，这是前所未有的HIV-1 Vpr，不仅提供了在全长分子中观察到的分子异质性的解释，但也表明，在体内Vpr的折叠和功能应取决于顺式/反式脯氨酸异构酶的活性，特别是作为两个脯氨酸残基的位置14和35显示出相当数量的顺式异构体。这一预测与我们最近的观察结果非常相关（Zander，K.，谢尔曼，M. P.，Tessmer，U.，Bruns，K.，Wray，V，Prechtel，A. T.，Schubert，E.，Henklein，P.，Luban，J.，Neidleman，J.，格林，W. C.的方法，Schubert，U.（2003）J.Biol.Chem.278，43170-43181），主要的细胞异构酶亲环素A和Vpr之间的功能性相互作用，这两种酶都被掺入HIV-1病毒体中。
The 96-residue human immunodeficiency virus (HIV) accessory protein Vpr serves manifold functions in the retroviral life cycle including augmentation of viral replication in non-dividing host cells, induction of G(2) cell cycle arrest, and modulation of HIV-induced apoptosis. Using a combination of dynamic light scattering, circular dichroism, and NMR spectroscopy the N terminus of Vpr is shown to be a unique domain of the molecule that behaves differently from the C-terminal domain in terms of self-association and secondary structure folding. Interestingly, the four highly conserved proline residues in the N terminus are predicted to have a high propensity for cis/trans isomerism. Thus the high resolution structure and folding of a synthetic N-terminal peptide (Vpr(1-40)) and smaller fragments thereof have been investigated. H-1 NMR data indicate Vpr(1-40) possesses helical structure between residues 17-32, and for the first time, this helix, which is bound by proline residues, was observed even in aqueous solution devoid of any detergent supplements. In addition, NMR data revealed that all of the proline residues undergo a cis/trans isomerism to such an extent that similar to40% of all Vpr molecules possess at least one proline in a cis conformation. This phenomenon of cis/trans isomerism, which is unprecedented for HIV-1 Vpr, not only provides an explanation for the molecular heterogeneity observed in the full-length molecule but also indicates that in vivo the folding and function of Vpr should depend on a cis/trans-proline isomerase activity, particularly as two of the proline residues in positions 14 and 35 show considerable amounts of cis isomers. This prediction correlates well with our recent observation (Zander, K., Sherman, M. P., Tessmer, U., Bruns, K., Wray, V., Prechtel, A. T., Schubert, E., Henklein, P., Luban, J., Neidleman, J., Greene, W. C., and Schubert, U. (2003) J. Biol. Chem. 278, 43170-43181) of a functional interaction between the major cellular isomerase cyclophilin A and Vpr, both of which are incorporated into HIV-1 virions.