title: Lytic activity of the recombinant staphylococcal bacteriophage PhiH5 endolysin active against Staphylococcus aureus in milk.
abstract: The endolysin gene (lysH5) from the genome of the Staphylococcus aureus bacteriophage PhiH5 was cloned in Escherichia coli and characterized. The lysH5 gene encoded a protein (LysH5) whose calculated molecular mass and pI were 53.7 kDa and 8.7, respectively. Comparative analysis revealed that LysH5 significantly resembled other murein hydrolases encoded by staphylococcal phages. The modular organization of LysH5 comprised three putative domains, namely, CHAP (cysteine, histidine-dependent amidohydrolase/peptidase), amidase (L-muramoyl-L-alanine amidase), and SH3b (cell wall recognition). In turbidity reduction assays, the purified protein lysed bovine and human S. aureus, and human Staphylococcus epidermidis strains. Other bacteria belonging to different genera were not affected. The lytic activity was optimal at pH 7.0, 37 degrees C, and sensitive to high temperatures. The purified protein was able to kill rapidly S. aureus growing in pasteurized milk and the pathogen was not detected after 4 h of incubation at 37 degrees C. As far as we know, this is the first report to assess the antimicrobial activity of a phage endolysin which might be useful for novel biocontrol strategies in dairying.
authors.affiliation: Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Apdo. 85. 33300-Villaviciosa, Asturias, Spain.
authors.forename: José María
authors.initials: JM
authors.lastname: Obeso
authors.forename: Beatriz
authors.initials: B
authors.lastname: Martínez
authors.forename: Ana
authors.initials: A
authors.lastname: Rodríguez
authors.forename: Pilar
authors.initials: P
authors.lastname: García
mesh_terms: D000581:Amidohydrolases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002417:Cattle; D003001:Cloning, Molecular; D010450:Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000821:virology; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015967:Gene Expression Regulation, Viral; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008892:Milk / Q000378:metabolism / Q000382:microbiology* / Q000821:virology; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000235:genetics / Q000378:metabolism; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism; D013204:Staphylococcus Phages / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D013211:Staphylococcus aureus / Q000378:metabolism / Q000821:virology*; D013696:Temperature; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D010450:Endopeptidases; D010447:Peptide Hydrolases; C001143:endolysin; D000581:Amidohydrolases; D009238:N-Acetylmuramoyl-L-alanine Amidase; C019665:amidase