ABSTRACTThe peptidoglycan (PG) layer protects bacteria from osmotic lysis and defines their shape. The class A penicillin-binding proteins (aPBPs) are PG synthases that possess both glycan polymerization and crosslinking activities needed for PG biogenesis. In Gram-negative bacteria. aPBPs require activation by outer membrane lipoproteins. https://oxfordshopes.shop/product-category/accessories-eyewear/