University of Stuttgart, Institute of Biomaterials and Biomolecular Systems, Department of Molecular Biology and Plant Virology, Pfaffenwaldring 57, 70550 Stuttgart, Germany.
University of Stuttgart, Institute of Biomaterials and Biomolecular Systems, Department of Molecular Biology and Plant Virology, Pfaffenwaldring 57, 70550 Stuttgart, Germany.
Virology. 2019 Mar;529:81-90. doi: 10.1016/j.virol.2019.01.018. Epub 2019 Jan 17.
One geminiviral gene encodes the capsid protein (CP), which can appear as several bands after electrophoresis depending on virus and plant. African cassava mosaic virus-Nigeria CP in Nicotiana benthamiana, however, yielded one band (~ 30 kDa) in total protein extracts and purified virions, although its expression in yeast yielded two bands (~ 30, 32 kDa). Mass spectrometry of the complete protein and its tryptic fragments from virions is consistent with a cleaved start M1, acetylated S2, and partial phosphorylation at T12, S25 and S62. Mutants for additional potentially modified sites (N223A; C235A) were fully infectious and formed geminiparticles. Separation in triton acetic acid urea gels confirmed charge changes of the CP between plants and yeast indicating differential phosphorylation. If the CP gene alone was expressed in plants, multiple bands were observed like in yeast. A high turnover rate indicates that post-translational modifications promote CP decay probably via the ubiquitin-triggered proteasomal pathway.
一种伴生病毒基因编码衣壳蛋白（CP），根据病毒和植物的不同，电泳后 CP 可呈现出几条带。然而，在本氏烟中，非洲木薯花叶病毒尼日利亚 CP 在总蛋白提取物和纯化的病毒粒子中仅产生一条带（30 kDa），尽管其在酵母中的表达产生了两条带（30、32 kDa）。来自病毒粒子的完整蛋白及其胰蛋白酶片段的质谱分析与裂解的起始 M1、乙酰化的 S2 以及 T12、S25 和 S62 处的部分磷酸化一致。针对其他潜在修饰位点（N223A；C235A）的突变体是完全有感染力的，并形成伴生颗粒。在 Triton 乙酸尿素凝胶中的分离证实了 CP 在植物和酵母之间的电荷变化，表明存在差异磷酸化。如果仅在植物中表达 CP 基因，则会像在酵母中一样观察到多条带。高周转率表明，翻译后修饰促进 CP 衰变，可能通过泛素触发的蛋白酶体途径。
