Mur1, a Streptococcus thermophilus peptidoglycan hydrolase devoid of a specific cell wall binding domain

The gene encoding Mur1, a Streptococcus thermophilus peptidoglycan hydrolas e, was cloned by homology with acmA, the Lactococcus lactis major autolysin gene. Mur1 is a 24.7-kDa protein endowed with a putative signal peptide. S equence analysis evidenced that Mur1 encompasses exactly the AcmA region co ntaining the catalytic domain, but lacks the one containing amino acid repe ats involved in cell wall binding. Mur1 appears to be expressed and cell-as sociated in S. thermophilus. as revealed by immunoblot analysis. These resu lts suggest that the cell wall attachment mode of Mur1 differs from that of most peptidoglycan hydrolases described so far. (C) 2000 Federation of Eur opean Microbiological Societies. Published by Elsevier Science B.V. All rig hts reserved.