Cloning and expression of Toxoplasma gondii GRA-4 recombinant protein as a toxoplasmosis diagnostic kit candidate

Abstract

Aim: The objective of this study was to produce recombinant protein GRA-4 (rGRA-4) of a local Toxoplasma gondii isolate as a candidate for a toxoplasmosis diagnosis kit in Escherichia coli BL21 (DE3) competent cells using pET SUMO plasmid. Materials and Methods: Samples used were stock T. gondii tachyzoites DNA from the Parasitology Laboratory, Faculty of Veterinary Medicine, Gadjah Mada University, Yogyakarta. Amplified GRA-4 polymerase chain reaction product of T. gondii tachyzoite DNA was cloned in the pET-SUMO TAR cloning vector. The GRA-4 gene from T. gondii local isolate was sequenced, followed by plasmid transformation, recombinant plasmid DNA isolation, and recombinant protein expression in DE3 competent cells. Results: The amplification product of GRA-4 T. gondii gene was 1036 bp, with 48 kDa molecular weight after expression in DE3 competent cells. An alignment of the amino acid sequence of GRA-4 from the local isolate which was cloned with GRA-4 was obtained from NCBI database and showed 99.61% homology to the predicted GRA-4 from the T. gondii Izatnagar isolate. Amino acid sequence of the predicted GRA-4 protein from local isolate was different at positions 19 and 304. Conclusion: This research cloned rGRA-4 in pET SUMO plasmid.