title: Characterization of a major 31-kilodalton peptidoglycan-bound protein of Legionella pneumophila.
abstract: A 31-kilodalton (kDa) protein was solubilized from the peptidoglycan (PG) fraction of Legionella pneumophila after treatment with either N-acetylmuramidase from the fungus Chalaropsis sp. or with mutanolysin from Streptomyces globisporus. The protein exhibited a ladderlike banding pattern by autoradiography when radiolabeled [( 35S]cysteine or [35S]methionine) PG material was extensively treated with hen lysozyme. The banding patterns ranging between 31 and 45 kDa and between 55 and 60 kDa resolved as a single 31-kDa protein when the material was subsequently treated with N-acetylmuramidase. Analysis of the purified 31-kDa protein for diaminopimelic acid by gas chromatography revealed 1 mol of diaminopimelic acid per mol of protein. When outer membrane PG material containing the major outer membrane porin protein was treated with N-acetylmuramidase or mutanolysin, both the 28.5-kDa major outer membrane protein and the 31-kDa protein were solubilized from the PG material under reducing conditions. In the absence of 2-mercaptoethanol, a high-molecular-mass complex (100 kDa) was resolved. The results of this study indicate that a 31-kDa PG-bound protein is a major component of the cell wall of L. pneumophila whose function may be to anchor the major outer membrane protein to PG. Finally, a survey of other Legionella species and other serogroups of L. pneumophila suggested that PG-bound proteins may be a common feature of this genus.
authors.affiliation: Department of Microbiology and Immunology, University of Tennessee, Memphis 38163.
authors.forename: C A
authors.initials: CA
authors.lastname: Butler
authors.forename: P S
authors.initials: PS
authors.lastname: Hoffman
mesh_terms: D000596:Amino Acids / Q000032:analysis; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000302:isolation & purification; D003553:Cystine / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006026:Glycoside Hydrolases; D006868:Hydrolysis; D007875:Legionella / Q000378:metabolism*; D008715:Methionine / Q000378:metabolism; D008970:Molecular Weight; D009113:Muramidase; D010457:Peptidoglycan / Q000096:biosynthesis* / Q000302:isolation & purification; D011485:Protein Binding; D013462:Sulfur Radioisotopes
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; D010457:Peptidoglycan; D013462:Sulfur Radioisotopes; D003553:Cystine; D008715:Methionine; D006026:Glycoside Hydrolases; D009113:Muramidase