This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Welker, N. E. Search for Related Content PubMed PubMed Citation Articles by Welker, N. E.

Structure of the Cell Wall of Bacillus stearothermophilus: Mode of Action of a Thermophilic Bacteriophage Lytic Enzyme

¹ Department of Biological Sciences, Northwestern University, Evanston, Illinois 60201

ABSTRACT

The mode of action of a bacteriophage lytic enzyme on cell walls of Bacillus stearothermophilus (NCA 1503-4R) has been investigated. The enzyme is an endopeptidase which catalyzes the hydrolysis of the L-alanyl-D-glutamyl linkage in peptide subunits of the cell wall peptidoglycan. Preliminary studies on the soluble components in lytic cell wall digests indicate that the glycan moiety is composed of alternating glucosamine and muramic acid; one half of the muramic acid residues contain the tripeptide, L-alanyl-D-glutamyldiaminopimelic acid, and the remaining residues contain the tetrapeptide, L-alanyl-D-glutamyldiaminopimeyl-D-alanine. Almost one half of the peptide subunits are involved in cross-linkages of chemotype I. A structure for the cell wall peptidoglycan is proposed in the light of these findings.