Prokaryotic expression and molecular characterization of surface antigen 3 (SAG 3) protein of Toxoplasma gondii

Abstract

Toxoplasmosis, caused by Toxoplasma gondii, is an important zoonotic disease with worldwide prevalence. In the present communication, we report molecular cloning, heterologous expression and characterization of 1158 bp complete open reading frame (ORF) of surface antigen 3 (SAG3) of T. gondii, RH strain, IVRI stock for the first time from India. The rSAG3 protein was expressed in E. coli as a 46kDa histidine-tagged fusion protein. Sequence analysis of the SAG3 coding sequence revealed 99.9% homology with the published sequence of T. gondii RH strain with substitution of a single base adenosine ‘A’ with guanosine ‘G’ at nucleotide position 397 in the ORF. Substitution of a single nucleotide resulted in substitution of aspartic acid (D) residue replacing asparagine (N).

Keywords

• Expression
• Molecular characterization
• RH Strain
• SAG3
• Toxoplasma gondii