Purification volume4
Neeta Pathaw and N K Chrungoo
North Eastern Hill University, India
: J Plant Physiol Pathol
Abstract
Plant diseases have emerged as a major threat to the global food security. Although, plants have no immune system; they possess a variety of defense mechanisms which include synthesis of pathogenesis related proteins in response to fungal/ bacterial infection. The paper reports on the purification and characterization of a 32kD protein which has growth inhibitory activity against Fusarium oxysporum, Trichoderma viride and Rhizopus stolonifer var stolonifer from seeds of Sechium edule (Jacq) Swartz. The protein, designated as SeAFP32, inhibited mycelial growth of Fusarium oxysporum, Trichoderma viride and Rhizopus stolonifer var stolonifer, with an IC50 of 10±0.14, 20±0.035 and 8±0.05 µg ml-1 respectively. SYTOX Green uptake assay indicated that the protein affected the permeability properties of the fungal cell membranes. MALDI-TOF/MS analysis of the tryptic digested 32kD SeAFP32 revealed 100% homology with β-glucosidase from Arabidopsis thaliana (acc. no. BAD94819). The 3D homology model of SeAFP32 developed with Modeller 9.10 with rice β-glucosidase protein (PDB ID: 3GNO) as template, confirmed it the high degree of homology of SeAFP32 with β-glucosidase family of proteins. In silico docking of p-nitrophenyl β-D-glucopyranoside (pNPG) on 3D model of SeAFP32 confirmed the presence and stearic position of the conserved Glu105, Ser75 and Glu161 on the docking domain. Glutamic acid at P’105 has been identified as the active site nucleophile required for the enzymatic hydrolysis of the glycosidic bond. neetapathaw@gmail.com
Biography
neetapathaw@gmail.com
