Identification and molecular characterization of an N-acetylmuramyl-L-alanine amidase Sle1 involved in cell separation of Staphylococcus aureus.
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.
Kajimura
Junko
J
Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences, 1-2-3 Kasumi Hiroshima City, Hiroshima 734-8553, Japan.
Fujiwara
Tamaki
T
Yamada
Sakuo
S
Suzawa
Yoshika
Y
Nishida
Tetsuya
T
Oyamada
Yoshihiro
Y
Hayashi
Ikue
I
Yamagishi
Jun-ichi
J
Komatsuzawa
Hitoshi
H
Sugai
Motoyuki
M
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
D001426:Bacterial Proteins; D010457:Peptidoglycan; D037521:Virulence Factors; D009238:N-Acetylmuramoyl-L-alanine Amidase