University of Delhi
Junior Research Fellow
Additional Specialties: Molecular Biology
Satya Prakash Chaurasia is a Phd student at Faculty of Science, University of Delhi. He did his MPhil, under the supervision of Prof Renu Deswal. The work was published in the Protein Journal in feb. 2017. He is currently doing his doctoral research work under same supervisor. The topic of research broadly covers the gold nano particle interaction with Brassica juncea.
Primary Affiliation: University of Delhi - Delhi, Delhi
Chaurasia, S.P. & Deswal, R. Protein J (2017). doi:10.1007/s10930-017-9698-x
The Protein Journal
The thiol–disulphide exchange regulates the activity of proteins by redox modulation. Many studies to analyze reactive oxygen species (ROS), particularly, hydrogen peroxide (H2O2) induced changes in the gene expression have been reported, but efforts to detect H2O2 modified proteins are comparatively few. Two-dimensional diagonal redox sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE) was used to detect polypeptides which undergo thiol–disulphide exchange in Brassica juncea seedlings following H2O2 (10 mM) treatment for 30 min. Eleven redox responsive polypeptides were identified which included cruciferin, NLI [Nuclear LIM (Lin11, Isl-1 & Mec-3 domains)] interacting protein phosphatase, RuBisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) large subunit, and myrosinase. Redox modulation of RuBisCO large subunit was further confirmed by western blotting. However, the small subunit of RuBisCO was not affected by these redox changes. All redox modulated targets except NLI interacting protein (although it contains two cysteines) showed oxidation sensitive cysteines by in silico analysis. Interestingly, interactome of cruciferin and myrosinase indicated that they may have additional function(s) beside their well-known roles in the seedling development and abiotic stress respectively. Cruciferin showed interactions with stress associated proteins like defensing-like protein 192 and 2-cys peroxiredoxin. Similarly, myrosinase showed interactions with nitrilase and cytochrome p450 which are involved in nitrogen metabolism and/or hormone biosynthesis. This simple procedure can be used to detect major stress mediated redox changes in other plants.
Cuticle forms the outermost layer of the aerial parts of the plants. Major function of cuticle is to protect from desiccation, UV radiation, pathogens and herbivores. It is the perception site for biotic and abiotic stress signaling. However, cuticle proteome studies are scarce. The leaf cuticle proteome of an economically important oil yielding crop, Brassica juncea was analyzed as its yield is decreased by multiple stress. Methodology: - Cuticle proteins were extracted using chloroform-methanol (2:1; v/v) followed by solvent evaporation at 55ºC. The residue was re-suspended in chloroform:water (2:1; v/v). The aqueous phase was precipitated and re-suspended in 50mM Tris-Cl pH 7.4 (Pyee et al., 1994). Purity was checked by cytosolic marker enzyme (Glucose-6-phosphate dehydrogenase) and RuBisCO. The proteins were resolved on SDS-PAGE and polypeptides were identified by MALDI-ToF/ToF. Antifreeze activity was detected using nanoliter osmometer. Results and Discussion: - Cuticle protein showed negligible cytoplasmic contamination (1.54%, G6PDH activity) and absence of RuBisCO. In all, 16 polypeptides were observed on a Colloidal CBB stained gel. Proteins such as myrosinase, involved in defense against herbivores; GDSL esterse/Lipase ESM1, required for modification and recycling of cutin; Xyloglucan endotransglucosylase/hydrolase protein 9, involved in cell wall metabolism; Succinate-semialdehyde dehydrogenase, MADS-box transcription Factor 32 and PsbP domain-containing protein 5 were identified. A polypeptide of ~10kDa a probable lipid transfer protein (LTP) was purified using PVPP. Cuticle proteins also showed antifreeze activity. Conclusion: - Protein candidates for cuticle synthesis and stress signaling were identified. A ~10kDa putative LTP is purified and its characterization is underway. Using high throughput techniques more candidates of signaling and stress related proteins would be identified.