Recombinant Expression of Domain III of Dengue Virus Envelope Protein (Serotype-1)

The aim of this study is to produce a recombinant antigen from the envelope protein of dengue virus serotype 1, as a dengue vaccine candidate. Therefore, we intend to study expression efficiency of domain III in a bacterial host. We used the following software: Megalign (sequence alignment); Modeller (protein structure prediction), and Optimizer (coding gene sequence optimization). The optimum coding sequence was synthesized and cloned in a pET21 expression vector. Stable protein expression and optimization of antigen production was performed in an Origami strain of E. coli. A consensus sequence for the domain III of dengue virus serotype 1 was produced by multiple alignment of sequences and named EDIII1. Next, we predicted EDIII1 properties by using bioinformatic software. To achieve a high expression level in the bacterial host, the coding sequence of this protein was optimized for appropriate CAI and GC content. The optimized gene was synthesized and cloned at the NdeI and XhoI sites of the pET21 expression vector in an E. coli DH5α strain. In order to have efficient protein expression and the formation of disulfide bounds, we optimized expression of EDIII1 in the Origami strain. Protein purification, using Histag affinity chromatography columns was performed and the results identified by Western blot analysis. The results of this study showed the efficiency of a bacterial system to highly express domain III of the dengue virus envelope protein.