title: Muralytic activity and modular structure of the endolysins of Pseudomonas aeruginosa bacteriophages phiKZ and EL.
abstract: Pseudomonas aeruginosa bacteriophage endolysins KZ144 (phage phiKZ) and EL188 (phage EL) are highly lytic peptidoglycan hydrolases (210 000 and 390 000 units mg(-1)), active on a broad range of outer membrane-permeabilized Gram-negative species. Site-directed mutagenesis indicates E115 (KZ144) and E155 (EL188) as their respective essential catalytic residues. Remarkably, both endolysins have a modular structure consisting of an N-terminal substrate-binding domain and a predicted C-terminal catalytic module, a property previously only demonstrated in endolysins originating from phages infecting Gram-positives and only in an inverse arrangement. Both binding domains contain conserved repeat sequences, consistent with those of some peptidoglycan hydrolases of Gram-positive bacteria. Fusions of these domains with green fluorescent protein immediately label all outer membrane-permeabilized Gram-negative bacteria tested, isolated P. aeruginosa peptidoglycan and N-acetylated Bacillus subtilis peptidoglycan, demonstrating the broad range of peptidoglycan-binding capacity by these domains. Specifically, A1 chemotype peptidoglycan and fully N-acetylated glucosamine units are essential for binding. Both KZ144 and EL188 appear to be a natural chimeric enzyme, originating from a recombination of a cell wall-binding domain encoded by a Bacillus or Clostridium species and a catalytic domain of an unknown ancestor.
authors: Division of Gene Technology, Department of Biosystems, Katholieke Universiteit Leuven, Kasteelpark Arenberg 21, B-3001 Leuven, Belgium. yves.briers@biw.kuleuven.be
authors: Yves
authors: Y
authors: Briers
authors: Guido
authors: G
authors: Volckaert
authors: Anneleen
authors: A
authors: Cornelissen
authors: Stijn
authors: S
authors: Lagaert
authors: Chris W
authors: CW
authors: Michiels
authors: Kirsten
authors: K
authors: Hertveldt
authors: Rob
authors: R
authors: Lavigne
mesh_terms: D000595:Amino Acid Sequence; D001435:Bacteriophages / Q000737:chemistry / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D010450:Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010457:Peptidoglycan / Q000378:metabolism; D011485:Protein Binding; D011550:Pseudomonas aeruginosa / Q000166:cytology / Q000821:virology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D010457:Peptidoglycan; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D010450:Endopeptidases; C001143:endolysin