title: Antimicrobial Protein Candidates from the Thermophilic Geobacillus sp. Strain ZGt-1: Production, Proteomics, and Bioinformatics Analysis.
abstract: A thermophilic bacterial strain, Geobacillus sp. ZGt-1, isolated from Zara hot spring in Jordan, was capable of inhibiting the growth of the thermophilic G. stearothermophilus and the mesophilic Bacillus subtilis and Salmonella typhimurium on a solid cultivation medium. Antibacterial activity was not observed when ZGt-1 was cultivated in a liquid medium; however, immobilization of the cells in agar beads that were subjected to sequential batch cultivation in the liquid medium at 60 °C showed increasing antibacterial activity up to 14 cycles. The antibacterial activity was lost on protease treatment of the culture supernatant. Concentration of the protein fraction by ammonium sulphate precipitation followed by denaturing polyacrylamide gel electrophoresis separation and analysis of the gel for antibacterial activity against G. stearothermophilus showed a distinct inhibition zone in 15-20 kDa range, suggesting that the active molecule(s) are resistant to denaturation by SDS. Mass spectrometric analysis of the protein bands around the active region resulted in identification of 22 proteins with molecular weight in the range of interest, three of which were new and are here proposed as potential antimicrobial protein candidates by in silico analysis of their amino acid sequences. Mass spectrometric analysis also indicated the presence of partial sequences of antimicrobial enzymes, amidase, and dd-carboxypeptidase.
authors.affiliation: Biotechnology, Department of Chemistry, Lund University, Lund SE-221 00, Sweden. rawana.alkhalili@biotek.lu.se.
authors.forename: Rawana N
authors.initials: RN
authors.lastname: Alkhalili
authors.affiliation: Center for Molecular Protein Science, Department of Chemistry, Lund University, Lund SE-221 00, Sweden. katja.bernfur@biochemistry.lu.se.
authors.forename: Katja
authors.initials: K
authors.lastname: Bernfur
authors.affiliation: Biotechnology, Department of Chemistry, Lund University, Lund SE-221 00, Sweden. tarek.dishisha@pharm.bsu.edu.eg.|Department of Microbiology and Immunology, Faculty of Pharmacy, Beni-Suef University, Beni-Suef 62511, Egypt. tarek.dishisha@pharm.bsu.edu.eg.
authors.forename: Tarek
authors.initials: T
authors.lastname: Dishisha
authors.affiliation: Biotechnology, Department of Chemistry, Lund University, Lund SE-221 00, Sweden. gashaw.mamo@biotek.lu.se.
authors.forename: Gashaw
authors.initials: G
authors.lastname: Mamo
authors.affiliation: Applied Microbiology, Department of Chemistry, Lund University, Lund SE-221 00, Sweden. jenny.schelin@tmb.lth.se.
authors.forename: Jenny
authors.initials: J
authors.lastname: Schelin
authors.affiliation: Department of Biology, Microbial Ecology Group, Lund University, Lund SE-221 00, Sweden. bjorn.canback@biol.lu.se.
authors.forename: Björn
authors.initials: B
authors.lastname: Canbäck
authors.affiliation: Center for Molecular Protein Science, Department of Chemistry, Lund University, Lund SE-221 00, Sweden. cecilia.emanuelsson@biochemistry.lu.se.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Emanuelsson
authors.affiliation: Biotechnology, Department of Chemistry, Lund University, Lund SE-221 00, Sweden. rajni.hatti-kaul@biotek.lu.se.
authors.forename: Rajni
authors.initials: R
authors.lastname: Hatti-Kaul
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D019295:Computational Biology / Q000379:methods*; D056506:Geobacillus / Q000378:metabolism*; D006358:Hot Temperature; D040901:Proteomics / Q000379:methods*
chemical_list: D000890:Anti-Infective Agents; D001426:Bacterial Proteins
keywords: Geobacillus; SDS-resistant proteins; antimicrobial proteins; cell-recycling; food spoilage bacteria; immobilization; thermophile