alpha-D-Man-(1->3)-beta-D-Glc-(1->4)-alpha-D-Glc-1-di-trans,octa-cis-undecaprenyl diphosphate + UDP-alpha-D-glucuronate = beta-D-GlcA-(1->2)-alpha-D-Man-(1->3)-beta-D-Glc-(1->4)-alpha-D-Glc-di-trans,octa-cis-undecaprenyl diphosphate + UDP + H(+) — reaction