before the transfer to membrane protein by MraY", as opposed to after in bacteria. Further work would be needed to connect these information into a coherent pathway. Effects of different bacterial medicines on pseudopeptidoglycan Lysozyme Lysozyme is a natural defense mechanism in humans that has the ability to break down peptidoglycan in bacterial cells. It degrades the peptidoglycan by targeting the β-1,4-glycosidic bonds that connect the alternating amino sugars in which it is composed of. This degradation of the glycosidic bonds within peptidoglycan cause the sugars to separate and inhibit the structural integrity of the peptidoglycan and the bacteria. Pseudopeptidoglycan, however, is composed of a different acidic amino sugar, which is N-acetyltalosaminuronic acid. This difference is the reason that it has β-1,3-glycosidic bonds (as opposed to the β-1,4-glycosidic bonds in bacteria). Lysozymes targets the linkage in peptidoglycan, and without that, becomes ineffective against pseudopeptidoglycan. Penicillin Penicillin is a group of antibiotics that have been effective against many bacterial infections. It attacks bacteria by targeting and inhibiting the transpeptidase that catalyzes the cross-linking of the amino sugars in peptidoglycan. However, peptidoglycan contains different amino sugars, and therefore, a different catalysis enzyme is used. The different amino acids cause antibiotics, that target cell walls like penicillin, to be ineffective against pseudopeptidoglycan. Taxonomic distribution PPG is found in the archaeal orders of Methanobacteriales and Methanopyrales. Some genera under these orders are: Methanobacterium Methanobrevibacter Methanothermobacter Methanothermus Methanosphaera Methanopyrus See also Cell wall Methanochondroitin Peptidoglycan References Further reading Membrane biology