Related Experiment Video
Updated: Aug 24, 2026
Expression of Recombinant Proteins in the Methylotrophic Yeast Pichia pastoris
Published on: February 25, 2010
Cloning and functional expression of a mungbean defensin VrD1 in Pichia pastoris
Ji-Jr Chen1, Gan-Hong Chen, Hui-Ching Hsu
1Graduate Institute of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung 202, Taiwan.
Abstract:
It was shown previously that a bacterially expressed mungbean defensin VrCRP exhibited both antifungal and insecticidal activities. To isolate this protein in a large quantity for its characterization, the defensin cDNA was expressed in Pichia pastoris and the recombinant defensin (rVrD1) was purified. The recombinant VrD1 was shown to inhibit the growth of fungi such as Fusarium oxysporum, Pyricularia oryza, Rhizoctonia solani, and Trichophyton rubrum and development of bruchid larva. The protein also inhibits in vitro protein synthesis. These biological activities are similar to that of the bacterially expressed defensin. Functional expression of VrD1 in Pichia pastoris provides a highly feasible system to study the structure-function relationship of VrD1 using the mutagenesis approach.
Insights
Recombinant mungbean defensin (rVrD1) expressed in Pichia pastoris retains antifungal and insecticidal properties. This feasible system allows further study of the defensin
Area of Science:
- Plant biochemistry
- Microbiology
- Molecular biology
Background:
- Mungbean defensin (VrCRP) previously demonstrated antifungal and insecticidal activities when expressed in bacteria.
- Large-scale isolation of VrCRP is necessary for detailed characterization and structure-function relationship studies.
Purpose of the Study:
- To achieve high-yield expression and purification of recombinant mungbean defensin (rVrD1) in Pichia pastoris.
- To confirm the biological activities of rVrD1, including antifungal, insecticidal, and protein synthesis inhibition.
- To establish a robust system for investigating the structure-function relationship of VrD1 via mutagenesis.
Main Methods:
- Cloning and expression of mungbean defensin cDNA in the Pichia pastoris yeast expression system.
- Purification of the recombinant defensin (rVrD1).
- Assays to evaluate antifungal activity against Fusarium oxysporum, Pyricularia oryza, Rhizoctonia solani, and Trichophyton rubrum.
- Assays to evaluate insecticidal activity against bruchid larvae.
- In vitro protein synthesis inhibition assays.
Main Results:
- Successfully purified recombinant VrD1 (rVrD1) from Pichia pastoris.
- rVrD1 exhibited significant inhibition against tested fungal species and bruchid larva development.
- rVrD1 demonstrated inhibition of in vitro protein synthesis.
- The observed biological activities of rVrD1 mirror those of the bacterially expressed defensin.
Conclusions:
- Pichia pastoris is a highly feasible system for the functional expression and large-scale production of mungbean defensin (rVrD1).
- The recombinant defensin rVrD1 retains the potent antifungal and insecticidal activities of the native protein.
- This expression system facilitates future structure-function studies of VrD1 using mutagenesis.
