title: Biochemical characterization of fruit-specific pathogenesis-related antifungal protein from basrai banana.
abstract: Pathogenesis-related/thaumatin like (PR-5/TL) antifungal protein from basrai banana was purified by using a simple protocol consisting of ammonium sulphate precipitation, affinity chromatography (Affi-gel blue gel), Q-Sepharose chromatography and gel filtration on Sephadex G-75. The purified protein with acidic character (pI 6.67) has molecular weight of 21.155 kDa, as determined by MALDI-TOF mass spectrometry. The purified protein shared N-terminal sequence homology with other TLPs. Crude banana extract inhibited the growth of Fusarium oxysporum, Aspergillus niger, Aspergillus fumigatus and Trichoderma viride with IC₅₀ values (determined by Probit analysis) 15 μM (slope=0.086, χ(2)=17.843, P=0.033), 17 μM (slope=0.183, χ(2)=61.533, P=0.011), 6.5 μM (slope=0.211, χ(2)=14.380, P=0.023) and 29.11 μM (slope=0.072, χ(2)=45.768, P=0.014). The purified antifungal protein repressed the growth of F. oxysporum, A. niger, A. fumigatus and T. viride with IC₅₀ values 9.7 μM (slope=0.056, χ(2)=11.538, P=0.021), 11.83 μM (slope=0.127, χ(2)=42.82, P=0.00), 4.61 μM (slope=0.150, χ(2)=10.199, P=0.017) and 21.43 μM (slope=0.053, χ(2)=33.693, P=0.00), respectively. The IC50 values of antifungal activity of crude banana extract were higher than the purified antifungal protein. It indicated that proteins in crude banana extract have antagonistic effect on the fungal growth. White bread is particularly vulnerable by fungal pathogens. Purified antifungal protein suppressed the growth of Aspergillus phoenicis and Aspergillus flavus on white bread suggesting that this protein can be used as a preservative in the bakery industry as well as in other relevant food processing industries.
authors.affiliation: Institute of Biochemistry and Biotechnology, University of the Punjab, Lahore 54590, Pakistan.
authors.forename: Nusrat
authors.initials: N
authors.lastname: Yasmin
authors.affiliation: Institute of Biochemistry and Biotechnology, University of the Punjab, Lahore 54590, Pakistan. Electronic address: mahjabeensaleem1@hotmail.com.
authors.forename: Mahjabeen
authors.initials: M
authors.lastname: Saleem
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D005591:Chemical Fractionation; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D002853:Chromatography, Liquid; D005658:Fungi / Q000187:drug effects*; D020128:Inhibitory Concentration 50; D007526:Isoelectric Point; D008826:Microbial Sensitivity Tests; D008970:Molecular Weight; D028521:Musa / Q000276:immunology / Q000378:metabolism*; D009548:Niger; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000935:Antifungal Agents; D010940:Plant Proteins
keywords: Antifungal protein; Banana; Characterization