Department of Integrative Structural and Computational Biology, La Jolla, CA 92037, USA; Doctoral Program in Chemical and Biological Sciences, The Scripps Research Institute, La Jolla, CA 92037, USA.
Department of Internal Medicine, Division of Infectious Diseases, Mayo Clinic, Rochester, MN 55902, USA; Department of Immunology, Mayo Clinic, Rochester, MN 55902, USA; Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55902, USA.
Virology. 2018 Mar;516:102-107. doi: 10.1016/j.virol.2018.01.007. Epub 2018 Jan 11.
The exterior minor protein IX of adenoviruses (AdVs) is a frequent target of attachment of antigens and the modified AdVs are being used as potent vaccine platforms. The organization of protein IX is disticntly different between human adenoviruses (HAdVs) and non-HAdVs. The analysis of solvent accessibility, based on the near atomic resolution structures, suggests that the C-terminal residues of IX are more accessible in non-HAdVs (e.g., bovine adenovirus) than in HAdVs. Although the C-terminal fusions of IX are displayed on the capsid surface, they could disrupt the formation of tetrameric coiled-coils (4-HLXB) in HAdVs due to steric hinderance, thereby potentially affecting the capsid stability. Importantly, the parallel-antiparallel arrangement of helices seen in the 4-HLXB is not condusive for IX C-terminal fusions in HAdVs. In contrast, the parallel trimeric C-terminal coiled-coils in non-HAdVs are unlikely to be affected by the attachment of antigens and more efficiently displayed on the AdV surface.
腺病毒（AdV）的外壳次要蛋白 IX 是抗原附着的常见靶点，经过修饰的 AdV 被用作有效的疫苗平台。人腺病毒（HAdV）和非 HAdV 之间的蛋白 IX 结构组织明显不同。基于近原子分辨率结构的溶剂可及性分析表明，非 HAdV（如牛腺病毒）中 IX 的 C 末端残基比 HAdV 更易接近。尽管 IX 的 C 末端融合在衣壳表面显示，但由于空间位阻，它们可能会破坏 HAdV 中四聚体卷曲螺旋（4-HLXB）的形成，从而可能影响衣壳稳定性。重要的是，在 4-HLXB 中观察到的平行-反平行排列的螺旋不适合 HAdV 中的 IX C 末端融合。相比之下，非 HAdV 中平行的三聚体 C 末端卷曲螺旋不太可能受到抗原附着的影响，并且更有效地在 AdV 表面显示。
