Computational evaluation of a fusion protein consisted of pertussis toxin and filamentous hemagglutinin from Bordetella pertussis to target Claudin-4 using C-terminal fragment of Clostridium perfringens enterotoxin

Pertussis, caused by Bordetella pertussis is still one of the controversial diseases worldwide due to its high prevalence in both the developed and the developing countries, especially among young children. As currently approved vaccines are not protective enough and provide Th2-type immune responses, there is an urgent need to develop new vaccines. In the current study, we applied the C-terminal fragment of Clostridium perferingens enterotoxin (C-CPE) as a delivery system and F1S1 fragment (Filamentous hemagglutinin (F1) and subunit 1 of pertussis toxin (S1) of B. pertussis to design a novel chimeric protein in silico, to target Claudin-4 receptors in mice lung cells. To achieve this goal, the primary, secondary and tertiary structures of the fusion protein were evaluated and the interaction of this protein with Claudin-4 receptors was studied. Molecular dynamic (MD) simulation analysis was performed to investigate the physical movement of atoms in a fixed period. According to the results; the full-length fusion protein has consisted of 807 amino acid residues which could be classified as a stable protein. There was a convenient consistency between the 3D predicted structure and the secondary structure prediction. An acceptable percentage of the residues were also detected in the most favored and allowed regions for the model. Based on HADDOCK results, there were no considerable differences between the interactions and MD simulation analysis, indicating that the predicted structures were stable during the simulation. Altogether, the data reported in this study represents the first step toward developing a nasal vaccine candidate against B. pertussis infection. Communicated by Ramaswamy H. Sarma

百日咳（Pertussis）由百日咳博德特菌（Bordetella pertussis）引发，尽管在全球范围内仍是颇具争议的传染病之一，因其在发达国家与发展中国家均呈现高流行态势，尤其在幼儿群体中高发。当前获批的疫苗保护效力不足，且仅能诱导Th2型免疫应答，因此亟需开发新型百日咳疫苗。本研究以产气荚膜梭菌肠毒素C端片段（C-terminal fragment of Clostridium perfringens enterotoxin, C-CPE）作为递送系统，联合百日咳博德特菌的丝状血凝素（Filamentous hemagglutinin, F1）与百日咳毒素亚基1（subunit 1 of pertussis toxin, S1）构成的F1S1片段，通过计算机模拟设计了一款新型嵌合蛋白，靶向小鼠肺细胞表面的Claudin-4受体。为达成该研究目标，团队对该融合蛋白的一级、二级与三级结构进行了评估，并探究了其与Claudin-4受体的相互作用；同时通过分子动力学（Molecular dynamic, MD）模拟分析，考察了该蛋白原子在固定时段内的物理运动情况。研究结果显示：全长融合蛋白共包含807个氨基酸残基，可归类为稳定蛋白；其三维预测结构与二级结构预测结果具有良好的一致性；该模型的氨基酸残基在拉氏构象图的最优惠区域与允许区域内的占比均处于可接受水平。根据HADDOCK分析结果，蛋白质相互作用与MD模拟分析结果无显著差异，表明预测结构在模拟过程中保持稳定。综上，本研究报道的数据为开发针对百日咳博德特菌感染的鼻用候选疫苗迈出了第一步。本文由Ramaswamy H. Sarma提交。