cHMc“e NAM-NAG LALa N-Acetylmuramic acid D-G D-Ale DAP DAP N-Acotylglucosamino D-Ala D-Glu -Ala -NAM- NAG 一 NAM-NAG I-ALa D-GlUNH D-Ala D-Ala-Gl-Gly-Gly-Gly -Gy-L-Lys L.Lys chal Peptide interridge D- GluNH L-Ala Peptidoglycan Pentaglycine NAM-NAG- cross-linking interridge 肽聚糖片的形成肽聚糖片的形成