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Optimization of the expression of surface antigen SAG1/2 of Toxoplasma gondii in the yeast Pichia pastoris
Tropical Biomedicine (2011)
  • Init Ithoi, University of Malaya
Surface antigens are the most abundant proteins found on the surface of the parasite Toxoplasma gondii. Surface antigen 1 (SAG1) and Surface antigen 2 (SAG2) remain the most important and extensively studied surface proteins. These antigens have been identified to play a role in host cell invasion, immune modulation, virulence attenuation. Recombinant SAG1/2 was cloned and expressed in yeast Pichia pastoris. We describe here optimization of critical parameters involved in high yield expression of the recombinant SAG1/2. Our results suggest that recombinant SAG1/2 were best expressed at 30 masculineC, pH 6 and 1% methanol as the carbon source by X33 Pichia cells. Additional optimizations included the downstream process such as ammonium sulphate precipitation and dialysis. The fusion protein was purified using Ni-NTA purification system with 80% recovery. The purified protein was 100% specific and sensitive in detection of toxoplasmosis.
  • Ammonium Sulfate/chemistry,
  • Antigens,
  • Protozoan/*biosynthesis/diagnostic use/genetics/isolation & purification,
  • Carbon/metabolism Chromatography,
  • Affinity,
  • Cloning,
  • Molecular,
  • Culture Media/chemistry,
  • Dialysis,
  • Fractional Precipitation,
  • *Gene Expression,
  • Hydrogen-Ion Concentration,
  • Methanol/metabolism,
  • Pichia/*genetics,
  • Protozoan Proteins/*biosynthesis/diagnostic use/genetics/isolation & purification Recombinant Fusion Proteins/biosynthesis/diagnostic use/genetics/isolation & purification,
  • Sensitivity and Specificity,
  • Serologic Tests/methods,
  • Temperature,
  • Toxoplasmosis/diagnosis.
Publication Date
December, 2011
Citation Information
Init Ithoi. "Optimization of the expression of surface antigen SAG1/2 of Toxoplasma gondii in the yeast Pichia pastoris" Tropical Biomedicine Vol. 28 Iss. 3 (2011)
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