Leyson Christina Lora M, Jordan Brian J, Jackwood Mark W
Poultry Diagnostic and Research Center, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, United States.
Poultry Diagnostic and Research Center, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, United States; Poultry Science Department, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA 30602, United States.
Infect Genet Evol. 2016 Dec;46:124-129. doi: 10.1016/j.meegid.2016.11.006. Epub 2016 Nov 9.
Infectious bronchitis virus is an important respiratory pathogen in chickens. The IBV S1 spike is a viral structural protein that is responsible for attachment to host receptors and is a major target for neutralizing antibodies. To date, there is no experimentally determined structure for the IBV S1 spike. In this study, we sought to find a predicted tertiary structure for IBV S1 using I-TASSER, which is an automated homology modeling platform. We found that the predicted structures obtained were robust and consistent with experimental data. For instance, we observed that all four residues (38, 43, 63, and 68) that have been shown to be critical for binding to host tissues, were found at the surface of the predicted structure of Massachusetts (Mass) S1 spike. Together with antigenicity index analysis, we were also able to show that Ma5 vaccine has higher antigenicity indices at residues close to the receptor-binding region than M41 vaccine, thereby providing a possible mechanism on how Ma5 achieves better protection against challenge. Examination of the predicted structure of the Arkansas IBV S1 spike also gave insights on the effect of polymorphisms at position 43 on the surface availability of receptor binding residues. This study showcases advancements in protein structure prediction and contributes useful, inexpensive tools to provide insights into the biology of IBV.
传染性支气管炎病毒是鸡群中一种重要的呼吸道病原体。传染性支气管炎病毒S1刺突蛋白是一种病毒结构蛋白，负责与宿主受体结合，是中和抗体的主要作用靶点。迄今为止，尚无传染性支气管炎病毒S1刺突蛋白的实验确定结构。在本研究中，我们试图使用I-TASSER（一种自动同源建模平台）来寻找传染性支气管炎病毒S1的预测三级结构。我们发现获得的预测结构是可靠的，并且与实验数据一致。例如，我们观察到，所有已被证明对结合宿主组织至关重要的四个残基（38、43、63和68），都位于马萨诸塞州（Mass）S1刺突蛋白预测结构的表面。结合抗原性指数分析，我们还能够表明，Ma5疫苗在靠近受体结合区域的残基处具有比M41疫苗更高的抗原性指数，从而为Ma5如何实现更好的攻毒保护提供了一种可能的机制。对阿肯色州传染性支气管炎病毒S1刺突蛋白预测结构的研究，也为43位多态性对受体结合残基表面可及性的影响提供了见解。本研究展示了蛋白质结构预测的进展，并提供了有用且廉价的工具，以深入了解传染性支气管炎病毒的生物学特性。
