Glycan strand cleavage by a lytic transglycosylase, MltD contributes to the expansion of peptidoglycan in Escherichia coli.

Peptidoglycan (PG) is a protective sac-like exoskeleton present in most bacterial cell walls. It is a large, covalently crosslinked mesh-like polymer made up of many glycan strands cross-bridged to each other by short peptide chains. Because PG forms a continuous mesh around the bacterial cytoplasmic membrane, opening the mesh is critical to generate space for the incorporation of new material during its expansion.

Peptidoglycan Remodeling by an L,D-Transpeptidase, LdtD during Cold Shock in Escherichia coli.

Peptidoglycan (PG) is a unique and essential component of the bacterial cell envelope. It is made up of several linear glycan polymers cross-linked through covalently attached stem peptides making it a fortified mesh-like sacculus around the bacterial cytosolic membrane. In most bacteria, including Escherichia coli, the stem peptide is made up of l-alanine (l-Ala), d-glutamate (d-Glu), meso-diaminopimelic acid (mDAP), d-alanine (d-Ala), and d-Ala with cross-links occurring either between d-ala and mDAP or between two mDAP residues.