Recent Advances in the Synthesis and Biological Applications of Peptidoglycan Fragments

The biosynthesis, breakdown, and modification of peptidoglycan (PG) play vital roles in both bacterial viability and in the response of human physiology to bacterial infection. Studies on PG biochemistry are hampered by the fact that PG is an inhomogeneous insoluble macromolecule. Chemical synthesis is therefore an important means to obtain PG fragments that may serve as enzyme substrates and elicitors of the human immune response. This review outlines the recent advances in the synthesis and biochemical studies of PG fragments, PG biosynthetic intermediates (such as Park's nucleotides and PG lipids), and PG breakdown products (such as muramyl dipeptides and anhydro-muramic acid-containing fragments). A rich variety of synthetic approaches has been applied to preparing such compounds since carbohydrate, peptide, and phospholipid chemical methodologies must all be applied.