A Staphylococcus aureus autolysin that has an N-acetylmuramoyl-L-alanine amidase domain and an endo-beta-N-acetylglucosaminidase domain: cloning, sequence analysis, and characterization.

The Tn551 insertion site of the autolysis-deficient Staphylococcus aureus mutant RUSAL2 was cloned and used to identify the autolysis gene atl in the parent strain, RN450. The open reading frame for atl was 3768 bp in length, encoding a deduced protein of 1256 amino acids and molecular size of 137,381 Da. The atl gene product is a bifunctional protein that has an amidase domain and an endo-beta-N-acetylglucosaminidase domain which must undergo proteolytic processing to generate the two extracellular lytic enzymes found in the culture broth of S. aureus.