Pseudomurein is found in the cell wall of Methcmobacterium species. The structure of pseudomurein is different from that of murein. N-acetyltalosaminuronate is linked to N—acetylglucosamine through a B-1,3-linkage in the place of B-1,4-linked N-acetyhnuramate. Consequently lysozyme does not hydrolyze pseudomurein. D-amino acids are not found in pseudomurein. Members of the genus Methcmoscmina have a cell wall consisting of polysaccharide, and the halophilic archaeon Halococcus has a cell wall of sulfonated polysac- Charide. Members of the genus Halobacterium and hyperthermophiljc archaea have glycoprotein as their cell wall, probably as an S—layer.