title: Purification and characterisation of an antifungal protein, MCha-Pr, from the intercellular fluid of bitter gourd (Momordica charantia) leaves.
abstract: An antifungal protein, designated MCha-Pr, was isolated from the intercellular fluid of bitter gourd (Momordica charantia) leaves during a screen for potent antimicrobial proteins from plants. The isolation procedure involved a combination of extraction, ammonium sulphate precipitation, gel filtration on Bio-Gel P-6, ion exchange chromatography on CM-Sephadex, an additional gel filtration on HiLoad 16/60 Superdex 30, and finally, HPLC on a SOURCE 5RPC column. Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry indicated that the protein had a molecular mass of 25733.46Da. Automated Edman degradation was used to determine the N-terminal sequence of MCha-Pr, and the amino acid sequence was identified as V-E-Y-T-I-T-G-N-A-G-N-T-P-G-G. The MCha-Pr protein has some similarity to the pathogenesis-related proteins from Atropa belladonna (deadly nightshade), Solanum tuberosum (potato), Ricinus communis (castor bean), and Nicotiana tabacum (tobacco). Analysis of the circular dichroism spectra indicated that MCha-Pr predominantly contains α-helix and β-sheet structures. MCha-Pr had inhibitory effects towards a variety of fungal species and the 50% inhibition of fungal growth (IC50) for Alternaria brassicae, Cercospora personata, Fusarium oxysporum, Mucor sp., and Rhizoctonia solani are 33 μM, 42 μM, 37 μM, 40 μM, and 48 μM, respectively. In addition, this antifungal protein can inhibit the germination of A. brassicae spores at 12.5 μM. These results suggest that MCha-Pr in bitter gourd leaves plays a protective role against phytopathogens and has a wide antimicrobial spectrum.
authors.affiliation: The Chongqing Key Laboratory of Molecular Biology of Plant Environmental Adaptations, 401331 Chongqing, China; The College of Life Science, Chongqing Normal University, 401331 Chongqing, China.
authors.forename: Beibei
authors.initials: B
authors.lastname: Zhang
authors.affiliation: The Chongqing Key Laboratory of Molecular Biology of Plant Environmental Adaptations, 401331 Chongqing, China; The College of Life Science, Chongqing Normal University, 401331 Chongqing, China.
authors.forename: Chengjian
authors.initials: C
authors.lastname: Xie
authors.affiliation: The Chongqing Key Laboratory of Molecular Biology of Plant Environmental Adaptations, 401331 Chongqing, China; The College of Life Science, Chongqing Normal University, 401331 Chongqing, China.
authors.forename: Yunming
authors.initials: Y
authors.lastname: Wei
authors.affiliation: The Chongqing Key Laboratory of Molecular Biology of Plant Environmental Adaptations, 401331 Chongqing, China; The College of Life Science, Chongqing Normal University, 401331 Chongqing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: The Chongqing Key Laboratory of Molecular Biology of Plant Environmental Adaptations, 401331 Chongqing, China; The College of Life Science, Chongqing Normal University, 401331 Chongqing, China. Electronic address: yangxy94@swu.edu.cn.
authors.forename: Xingyong
authors.initials: X
authors.lastname: Yang
mesh_terms: D000595:Amino Acid Sequence; D000935:Antifungal Agents / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D005658:Fungi / Q000187:drug effects; D008969:Molecular Sequence Data; D029777:Momordica charantia / Q000737:chemistry* / Q000235:genetics; D018515:Plant Leaves / Q000737:chemistry / Q000235:genetics; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D000935:Antifungal Agents; D010940:Plant Proteins
keywords: Antifungal protein; Bitter gourd; Intercellular fluid; Isolation