Molecular analysis of Toxoplasma gondii Surface Antigen 1 (SAG1) gene cloned from Toxoplasma gondii DNA isolated from Java']Javanese acute toxoplasmosis

Toxoplasma gondii Surface Antigen 1 (SAG1) is often used as a diagnostic tool due to its immunodominant-specific as antigen. However, data of the Toxoplasma gondii SAG1 protein from Indonesian isolate is limited. To study the protein, genomic DNA was isolated from a Javanese acute toxoplasmosis blood samples patient. A complete coding sequence of Toxoplasma gondii SAG1 was cloned and inserted into an Escherichia coli expression plasmid and sequenced. The sequencing results were subjected to bioinformatics analysis. The Toxoplasma gondii SAG1 complete coding sequences were successfully cloned. Physicochemical analysis revealed the 336 aa of SAG1 had 34.7 kDa of weight. The isoelectric point and aliphatic index were 8.4 and 78.4, respectively. The N-terminal methionine half-life in Escherichia coli was more than 10 hours. The antigenicity, secondary structure, and identification of the HLA binding motifs also had been discussed. The results of this study would contribute information about Toxoplasma gondii SAG1 and benefits for further works willing to develop diagnostic and therapeutic strategies against the parasite.