Further studies on the incorporation of d-methionine into the bacterial cell wall

Abstract

d-Methionine is incorporated into the cell walls of Alcaligenes fecalis thereby blocking further synthesis of this stucture. In the present paper evidence is presented demonstrating incorporation of d-methionine into a component of the phenol-insoluble cell wall which may be liberated by lysozyme (N-acetylmuramide glycanohydrolase, EC 3.2.1.17). Chromatography of the products of lysozyme digestion indicate that d-methionine is incorporated into a complex structure, which can be broken into different units by lysozyme. Analysis has shown that neither the amino nor the carboxyl groups of methionine are free when this amino acid is incorporated into the cell wall. Electron-microscopic studies have revealed lesions in the wall of cells grown in the presence of d-methionine as well as the liberation of firbous material from the cell wall. This fibrous material appears to be lysozyme sensitive and may possibly originate from a more compact subunit.