title: Isolation, purification and characterization of antimicrobial protein from seedlings of Bauhinia purpurea L.
abstract: A novel antimicrobial protein was purified from the seedlings of Bauhinia purpurea by sequential procedures entailing ammonium sulfate precipitation, cation exchange chromatography, preparative native-PAGE and a yield of 2.7% was obtained from the crude extract. The purified antimicrobial protein appeared as a single protein band on SDS-PAGE with the molecular mass of 20.9 kDa. Purified antimicrobial protein exhibited a potent antimicrobial activity against both Gram-positive and Gram-negative bacteria. Analysis of the trypsin digested peptides of purified protein using the MALDI-TOF MS/MS resulted in the identification of 174 amino acids. The purified protein had an optimum of pH of 5.5 and was stable at 35 °C for exhibiting its maximal antibacterial activity. The addition of metal ions such as Mn(2+) and Ca(2+) to the purified protein enhanced the antimicrobial activity of purified protein. The MIC of purified protein against Bacillus cereus and Escherichia coli were 13 μg/ml and 15 μg/ml, respectively. The purified protein digested the peptidoglycan layer of bacteria which was visualized by TEM analysis.
authors.affiliation: Centre for Advanced Studies in Botany, University of Madras, Guindy Campus, Chennai, Tamil Nadu 600 025, India.
authors.forename: Muthu
authors.initials: M
authors.lastname: Sakthivel
authors.affiliation: Centre for Advanced Studies in Botany, University of Madras, Guindy Campus, Chennai, Tamil Nadu 600 025, India. Electronic address: palani7@unom.ac.in.
authors.forename: Perumal
authors.initials: P
authors.lastname: Palani
mesh_terms: D000645:Ammonium Sulfate / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D036481:Bauhinia / Q000737:chemistry*; D002266:Carboxymethylcellulose Sodium / Q000737:chemistry; D005591:Chemical Fractionation; D011232:Chemical Precipitation; D008670:Metals / Q000737:chemistry; D008826:Microbial Sensitivity Tests; D008970:Molecular Weight; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D036226:Seedlings / Q000737:chemistry*; D012639:Seeds / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013696:Temperature
chemical_list: D000900:Anti-Bacterial Agents; D008670:Metals; D010940:Plant Proteins; D012997:Solvents; D002266:Carboxymethylcellulose Sodium; D000645:Ammonium Sulfate
keywords: Antimicrobial activity; Antimicrobial protein; Bauhinia purpurea; Seedlings