title: Lysozyme inhibitor conferring bacterial tolerance to invertebrate type lysozyme.
abstract: Invertebrate (I-) type lysozymes, like all other known lysozymes, are dedicated to the hydrolysis of peptidoglycan, the major bacterial cell wall polymer, thereby contributing to the innate immune system and/or digestive system of invertebrate organisms. Bacteria on the other hand have developed several protective strategies against lysozymes, including the production of periplasmic and/or membrane-bound lysozyme inhibitors. The latter have until now only been described for chicken (C-) type lysozymes. We here report the discovery, purification, identification and characterization of the first bacterial specific I-type lysozyme inhibitor from Aeromonas hydrophila, which we designate PliI (periplasmic lysozyme inhibitor of the I-type lysozyme). PliI has homologs in several proteobacterial genera and contributes to I-type lysozyme tolerance in A. hydrophila in the presence of an outer membrane permeabilizer. These and previous findings on C-type lysozyme inhibitors suggest that bacterial lysozyme inhibitors may have an important function, for example, in bacteria-host interactions.
authors.affiliation: Laboratory of Food Microbiology, Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001, Leuven, Belgium.
authors.forename: J M
authors.initials: JM
authors.lastname: Van Herreweghe
authors.forename: L
authors.initials: L
authors.lastname: Vanderkelen
authors.forename: L
authors.initials: L
authors.lastname: Callewaert
authors.forename: A
authors.initials: A
authors.lastname: Aertsen
authors.forename: G
authors.initials: G
authors.lastname: Compernolle
authors.forename: P J
authors.initials: PJ
authors.lastname: Declerck
authors.forename: C W
authors.initials: CW
authors.lastname: Michiels
mesh_terms: D016980:Aeromonas hydrophila / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001483:Base Sequence; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D007448:Invertebrates / Q000378:metabolism; D008969:Molecular Sequence Data; D009113:Muramidase / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D009113:Muramidase