Reaction: ADP-L-glycero-β-D-manno-heptose + an α-Hep-(1→3)-4-O-phospho-α-Hep-(1→5)-[α-Kdo-(2→4)]-α-Kdo-(2→6)-[lipid A] = ADP + an α-Hep-(1→7)-α-Hep-(1→3)-4-O-phospho-α-Hep-(1→5)-[α-Kdo-(2→4)]-α-Kdo-(2→6)-[lipid A]
Glossary: Lipid A is a lipid component of the lipopolysaccharides (LPS) of Gram-negative bacteria. It consists of two glucosamine units connected by a β(1→6) bond and decorated with four to seven acyl chains and up to two phosphate groups.
Hep = L-glycero-D-manno-heptose
Other name(s): waaQ (gene name); rfaQ (gene name)
Systematic name: ADP-L-glycero-β-D-manno-heptose:an α-Hep-(1→3)-4-O-phospho-α-Hep-(1→5)-[α-Kdo-(2→4)]-α-Kdo-(2→6)-[lipid A] heptoseI 7-α-heptosyltransferase
Comments: The enzyme catalyses a glycosylation step in the biosynthesis of the inner core oligosaccharide of the lipopolysaccharide (endotoxin) of some Gram-negative bacteria.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Mudapaka, J. and Taylor, E.A. Cloning and characterization of the Escherichia coli heptosyltransferase III: Exploring substrate specificity in lipopolysaccharide core biosynthesis. FEBS Lett. 589 (2015) 1423-1429. [PMID: 25957775]