(KDO)3 lipid IVA (2 4) 3 deoxy D manno octulosonic acid transferase

(KDO)3-lipid IVA (2-4) 3-deoxy-D-manno-octulosonic acid transferase (EC 2.4.99.15, KDO transferase, waaA (gene), kdtA (gene), 3-deoxy-D-manno-oct-2-ulosonic acid transferase, 3-deoxy-manno-octulosonic acid transferase) is an enzyme with systematic name CMP-3-deoxy-D-manno-oct-2-ulosonate:(KDO)3-lipid IVA 3-deoxy-D-manno-oct-2-ulosonate transferase ((2->4) glycosidic bond-forming). This enzyme catalyses the following chemical reaction

alpha-Kdo-(2->8)-alpha-Kdo-(2->4)-alpha-Kdo-(2->6)-lipid IVA + CMP-alpha-Kdo ⇌ alpha-Kdo-(2->8)-[alpha-Kdo-(2->4)]-alpha-Kdo-(2->4)-alpha-Kdo-(2->6)-lipid IVA + CMP

The enzyme from Chlamydia psittaci transfers four KDO residues to lipid A, forming a branched tetrasaccharide.