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Identification and molecular characterization of an N ‐acetylmuramyl‐ l ‐alanine amidase Sle1 involved in cell separation of Staphylococcus aureus
Author(s) -
Kajimura Junko,
Fujiwara Tamaki,
Yamada Sakuo,
Suzawa Yoshika,
Nishida Tetsuya,
Oyamada Yoshihiro,
Hayashi Ikue,
Yamagishi Jun–ichi,
Komatsuzawa Hitoshi,
Sugai Motoyuki
Publication year - 2005
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2005.04881.x
Subject(s) - autolysin , peptidoglycan , biology , mutant , staphylococcus aureus , microbiology and biotechnology , amidase , gene , biochemistry , genetics , enzyme , bacteria
Summary 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 .