Phosphoenolpyruvate + D-Man-beta-(1->4)-GlcA-beta-(1->2)-D-Man-alpha-(1->3)-D-Glc-beta-(1->4)-D-Glc-alpha-1-diphospho-ditrans,octacis-undecaprenol <=> 4,6-CH3(COO-)C-D-Man-beta-(1->4)-D-GlcA-beta-(1->2)-D-Man-alpha-(1->3)-D-Glc-beta-(1->4)-D-Glc-alpha-1-diphospho-ditrans,octacis-undecaprenol + Orthophosphate