2.4.99.12 - 2.4.99.12 expressed in a rough mutant (Re chemotype) of Escherichia coli (strain F515) that contains an lipopolysaccharide with only two alpha 2-4-linked Kdo residues. Recombinant strains are able to add the immunodominant Kdo residue in alpha 2-8-linkage to the parental lipopolysaccharide. Comparison of nucleotide and the deduced amino acid sequences of gseA of Chlamydia psittaci 6BC and Chlamydia trachomatis L 2.4.99.12 expressed in Corynebacterium glutamicum 2.4.99.12 expressed in Escherichia coli CMR300 cells lacking Kdo-transferase 2.4.99.12 expressed in Escherichia coli Top10 cells 2.4.99.12 expression in Escherichia coli. Chlamydial Kdo transferases can replace in Escherichia coli K-12 the host's Kdo transferase and retain the product specificities described in their natural background. WaaA from Chlamydia psittaci transfers predominantly four Kdo residues to lipid A, forming a branched tetrasaccharide with the structure alpha-Kdo-(2,8)-[alpha-Kdo-(2,4)]-alpha-Kdo-(2,4)-alpha-Kdo 2.4.99.12 heterologous expression of the Aquifex aeolicus waaA gene in a newly constructed Escherichia coli waaA suppressor strain results in synthesis of lipid IV(A) precursors substituted with one Kdo sugar 2.4.99.12 introduction of gseA into an Escherichia coli mutant with a thermolabile kdtA gene product endows cell extracts with the ability to transfer not only the third but also the first two Kdos to lipid A precursors, the Chlamydia trachomatis enzyme is at least trifunctional 2.4.99.12 the gene is expressed in the Gram-positive host Corynebacterium glutamicum. Both Escherichia coli strains which express waaA and kdkA from Haemophilus influenzae synthesize an lipopolysaccharide containing a single Kdo residue that was exclusively phosphorylated at position 4