Pseudopeptidoglycan

Pseudopeptidoglycan (also known as pseudomurein) is a major cell wall component of some Archaea that differs from bacterial peptidoglycan in chemical structure, but resembles bacterial peptidoglycan in function and physical structure. The basic components are N-acetylglucosamine and N-acetyltalosaminuronic acid (peptidoglycan has N-acetylmuramic acid instead), which are linked by β-1,3-glycosidic bonds. Lysozyme, a host defense mechanism present in human secretions (eg. saliva and tears), is ineffective against organisms with pseudopeptidoglycan cell walls. Lysozyme can break β-1,4-glycosidic bonds to degrade peptidoglycan; however, pseudopeptidoglycan has β-1,3-glycosidic bonds, rendering lysozyme useless.