title: Purification and partial characterization of a thermostable antimicrobial protein from Bacillus subtilis FB123.
abstract: Antimicrobial proteins/peptides have attracted much attention because of their potential use in the industrial setting. In the present study, a thermostable antimicrobial protein (BSAMP) was purified from the culture supernatant of Bacillus subtilis FB123 by ammonium sulfate precipitation, gel chromatography on Sephacryl S-200 High Resolution, and ion exchange chromatography on DEAE Sepharose Fast Flow column. The molecular weight of the purified BSAMP was 54 kDa, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis both in the absence and presence of β-mercaptoethanol. Its isoelectric point was determined to be 5.24 by isoelectric focusing electrophoresis. Periodic acid-Schiff staining revealed BSAMP to be a glycoprotein. Maximum activity was obtained at pH 6.0, with over 79% maximum activity retained at pH 3.0-5.0 and pH 7.0-9.0, respectively. BSAMP was shown to be highly thermostable, as its activity did not change obviously after treatment at 100 °C. However, it was partially sensitive to papain, trypsin, and alkali proteases. Finally, the bacterial protein exhibited broad-spectrum antimicrobial activity against several pathogenic organisms. These findings suggested that BSAMP should be further developed as a natural antibacterial agent for disease prevention in aquiculture and agriculture.
authors.affiliation: Engineering Research Center of Industrial Microbiology, Ministry of Education, Fujian Normal University, Fuzhou, 350108, Fujian, People's Republic of China, shibh@fjnu.edu.cn.
authors.forename: Bihong
authors.initials: B
authors.lastname: Shi
authors.forename: Hong
authors.initials: H
authors.lastname: Zheng
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Huang
authors.forename: Xiuzhen
authors.initials: X
authors.lastname: Luo
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Luo
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D001412:Bacillus subtilis / Q000737:chemistry* / Q000378:metabolism; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003470:Culture Media / Q000737:chemistry / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005658:Fungi / Q000187:drug effects / Q000254:growth & development; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008970:Molecular Weight; D055550:Protein Stability; D013696:Temperature
chemical_list: D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D003470:Culture Media