A novel 3-deoxy-D-manno-octulosonic acid transferase from Chlamydia trachomatis required for expression of the genus-specific epitope.
DNA cloned from Chlamydia trachomatis is able to direct the formation of the genus-specific lipopolysaccharide epitope of chlamydiae in enteric Gram-negative bacteria. We now demonstrate that a single C. trachomatis gene (gseA) is sufficient to impart this trait to Escherichia coli. The deduced amino acid sequence of gseA shows 23% identity (66% similarity) to kdtA, an E. coli gene that codes for a bifunctional enzyme catalyzing the addition of two 3-deoxy-D-manno-octulosonic acid (Kdo) residues to lipid A precursors (Clementz, T., and Raetz, C. R. H. (1991) J. Biol. Chem. 266, 9687-9696). Extracts of E. coli expressing gseA transfer at least one additional Kdo unit from CMP-Kdo to precursors already bearing the two Kdo residues attached by the kdtA gene product. Introduction of gseA into an E. 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, demonstrating that the C. trachomatis enzyme is at least trifunctional. Given the similarities of these two Kdo transferases and the essentiality of Kdo in Gram-negative bacteria, lipopolysaccharide biosynthesis may be a target for development of novel drugs effective against chlamydiae.
Belunis
C J
CJ
Department of Biochemistry, Merck Research Laboratories, Rahway, New Jersey 07065.
Mdluli
K E
KE
Raetz
C R
CR
Nano
F E
FE
D000595:Amino Acid Sequence; D001483:Base Sequence; D002692:Chlamydia trachomatis / Q000201:enzymology*; D002855:Chromatography, Thin Layer; D003001:Cloning, Molecular; D000939:Epitopes / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D008969:Molecular Sequence Data; D010957:Plasmids; D014176:Protein Biosynthesis; D011995:Recombination, Genetic; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic; D014166:Transferases / Q000235:genetics* / Q000276:immunology
D000939:Epitopes; D014166:Transferases; C019917:3-deoxy-D-manno-octulosonate transferase