A novel glycan polymerase that synthesizes uncross-linked peptidoglycan in Escherichia coli

A simple and efficient procedure to assay peptidoglycan synthesis in vitro was established. By this procedure, a novel activity for glycan polymerization in Escherichia coli was found in the fraction containing no detectable penicillin-binding protein (PBP). This polymerase activity was relatively insensitive to moenomycin, showed requirement for Ca2+ or Mn2+ but not for Mg2+, and led to production of uncross-linked glycan chains. These properties distinguished the glycan polymerase from the activities shown by the fractions containing PBPs. The glycan polymerase catalyzing polymerization of glycan units from lipid intermediates was purified and identified as a protein of 34 kDa.