title: Identification and molecular characterization of an N-acetylmuramyl-L-alanine amidase Sle1 involved in cell separation of Staphylococcus aureus.
abstract: We purified a peptidoglycan hydrolase involved in cell separation from a Staphylococcus aureus atl null mutant and identified its gene. Characterization of the gene product shows a 32 kDa N-acetylmuramyl-L-alanine amidase that we designated Sle1. Analysis of peptidoglycan digests showed Sle1 preferentially cleaved N-acetylmuramyl-L-Ala bonds in dimeric cross-bridges that interlink the two murein strands in the peptidoglycan. An insertion mutation of sle1 impaired cell separation and induced S. aureus to form clusters suggesting Sle1 is involved in cell separation of S. aureus. The Sle1 mutant revealed a significant decrease in pathogenesis using an acute infection mouse model. Atl is the major autolysin of S. aureus, which has been implicated in cell separation of S. aureus. Generation of an atl/sle1 double mutant revealed that the mutant cell separation was heavily impaired suggesting that S. aureus uses two peptidoglycan hydrolases, Atl and Sle1, for cell separation. Unlike Atl, Sle1 is not directly involved in autolysis of S. aureus.
authors.affiliation: Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences, 1-2-3 Kasumi Hiroshima City, Hiroshima 734-8553, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Kajimura
authors.forename: Tamaki
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Sakuo
authors.initials: S
authors.lastname: Yamada
authors.forename: Yoshika
authors.initials: Y
authors.lastname: Suzawa
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Nishida
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Oyamada
authors.forename: Ikue
authors.initials: I
authors.lastname: Hayashi
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Yamagishi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Komatsuzawa
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Sugai
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D002455:Cell Division; D004195:Disease Models, Animal; D017353:Gene Deletion; D005798:Genes, Bacterial; D051379:Mice; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016254:Mutagenesis, Insertional; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D010457:Peptidoglycan / Q000378:metabolism; D010641:Phenotype; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000166:cytology / Q000201:enzymology* / Q000472:pathogenicity / Q000648:ultrastructure; D013379:Substrate Specificity; D037521:Virulence Factors / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D010457:Peptidoglycan; D037521:Virulence Factors; D009238:N-Acetylmuramoyl-L-alanine Amidase