Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, P. O. Box 14115-111, Tehran, Iran.
Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, P. O. Box 14115-111, Tehran, Iran.
Microb Pathog. 2020 Oct;147:104386. doi: 10.1016/j.micpath.2020.104386. Epub 2020 Jul 11.
The SAG1 is a tachyzoite-specific protein critical for Toxoplasma gondii (T. gondii) adhesion to surface receptors of the host cells. In this study we've comprehensively excavated the sequence of SAG1 using online bioinformatics servers toward better vaccine design against toxoplasmosis. Web-based tools were used to assess the physico-chemical properties, post-translational modifications (PTMs), transmembrane domains, subcellular localization, secondary and 3D structures, as well as B-cell, Cytotoxic T cells (CTL) and major histocompatibility complex (MHC) epitopes. The 336 amino acid sequence possessed a molecular weight of 34829.02 D, aliphatic index of 80.15 and GRAVY score of 0.129. There was 47 PTM sites without any transmembrane domains. Also, the SAG1 protein was appointed to be immunogen and non-allergen. The secondary structure comprised 62.5% random coil, 26.79% extended strand and 10.71% alpha helix. Ramachandran plot of the refined model demonstrated 94.4% residues in the favored region, 4.8% in allowed region and 0.8% in outlier region. Additionally, various potential B-cell (linear and conformational), CTL and HTL epitopes were predicted for T. gondii SAG1. This in silico investigation would be a premise for appropriate immunization strategies against toxoplasmosis. More studies are anticipated to be done empirically using SAG1 immunoprotective epitopes combined with other antigenic compounds.
SAG1 是速殖子特异性蛋白，对于刚地弓形虫（Toxoplasma gondii，T. gondii）黏附宿主细胞表面受体至关重要。在本研究中，我们使用在线生物信息学服务器全面挖掘了 SAG1 的序列，以期更好地设计针对弓形虫病的疫苗。我们使用基于网络的工具来评估其理化性质、翻译后修饰（PTMs）、跨膜结构域、亚细胞定位、二级和 3D 结构以及 B 细胞、细胞毒性 T 细胞（CTL）和主要组织相容性复合物（MHC）表位。该 336 个氨基酸序列的分子量为 34829.02 D，脂肪指数为 80.15，克分子体积（GRAVY）得分为 0.129。有 47 个 PTM 位点没有任何跨膜结构域。此外，SAG1 蛋白被指定为免疫原而非过敏原。二级结构由 62.5%的无规则卷曲、26.79%的延伸链和 10.71%的α螺旋组成。精修模型的 Ramachandran 图谱显示 94.4%的残基处于优先区域，4.8%处于允许区域，0.8%处于边缘区域。此外，还预测了刚地弓形虫 SAG1 的各种潜在 B 细胞（线性和构象）、CTL 和 HTL 表位。这项计算机研究将为针对弓形虫病的适当免疫策略提供前提。预计将使用 SAG1 免疫保护表位与其他抗原性化合物结合进行更多的实验研究。
