Laboratório de Genômica Estrutural, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Sci Rep. 2019 Feb 26;9(1):2829. doi: 10.1038/s41598-019-39185-3.
The dengue virus 2 capsid protein (DENV2C) plays a primary structural role in the protection of the viral genome and is crucial for nucleocapsid assembly. In this study, we generated single mutants of DENV2C at L50 and L54 residues of the α2 helix, which was shown to interfere with the integration of the capsid into lipid droplets, and at residues L81 and I88 located in the α4 helix, which was shown to affect viral assembly. We demonstrated that the oligomeric states of DENV2C and its mutants exist primarily in the dimeric state in solution. All single-point mutations introduced in DENV2C promoted reduction in protein stability, an effect that was more pronounced for the L81N and I88N mutants, but not protein unfolding. All the single-point mutations affected the ability of DEN2C to interact with RNA. We concluded that mutations in the α2-α2' and α4-α4' dimer interfaces of DENV2C affect the structural stability of the protein and impair RNA-capsid interaction. These effects were more pronounced for mutations at the L81 and I88 residues in the α4 helix. These results indicate the importance of the α4-α4' dimer interface, which could be studied as a potential target for drug design in the future.
登革病毒 2 衣壳蛋白 (DENV2C) 在保护病毒基因组方面发挥主要结构作用，对于核衣壳组装至关重要。在这项研究中，我们在α2 螺旋的 L50 和 L54 残基以及位于α4 螺旋的 L81 和 I88 残基上生成了 DENV2C 的单点突变体，这些残基被证明会干扰衣壳与脂滴的整合，以及影响病毒组装。我们证明 DENV2C 及其突变体的寡聚态主要以二聚体形式存在于溶液中。DENV2C 中的所有单点突变都导致蛋白稳定性降低，L81N 和 I88N 突变体的影响更为明显，但不会导致蛋白展开。所有单点突变都影响 DEN2C 与 RNA 的相互作用能力。我们得出结论，DENV2C 的α2-α2'和α4-α4'二聚体界面突变会影响蛋白的结构稳定性，并损害 RNA-衣壳相互作用。在α4 螺旋的 L81 和 I88 残基上的突变影响更为明显。这些结果表明α4-α4'二聚体界面的重要性，该界面可能成为未来药物设计的潜在靶点。
