Structural analysis of the lipopolysaccharide from Chlamydia trachomatis serotype L2

The lipopolysaccharide (LPS) of Chlamydia trachomatis L2 was isolated from tissue culture-grown elementary bodies using a modified phenol/water procedure followed by extraction with phenol/chloroform/light petroleum. From a total of 5 x 10(4) cm(2) of infected monolayers, 22.3 mg of LPS were obtained. Compositional analysis indicated the presence of 3-deoxy-D-manno-oct-2-ulopyranosonic acid (Kdo), GlcN, phosphorus, and fatty acids in a molar ratio of 2.8:2:2.1:4.5. Matrix-assisted laser-desorption ionization mass spectrometry performed on the de-O-acylated LPS gave a major molecular ion peak at mit 1781.1 corresponding to a molecule of 3 Kdo, 2 GlcN, 2 phosphates, and two 3-hydroxyeicosanoic acid residues. The structure of deacylated LPS obtained after successive treatment with hydrazine and potassium hydroxide was determined by 600 MHz NMR spectroscopy as Kdo alpha 2 --> 8Kdo alpha 2 --> 4Kdo alpha 2 --> 6D --> GlcpN beta 1 --> 6D-GlcpN alpha 1, 4-bisphosphate. These data, together with those published recently on the acylation pattern of chlamydial lipid A (Qureshi, N,, Kaltashov, I., Walker, K,, Doroshenko, V,, Cotter, R, J,, Takayama, K, Sievert, T, R,, Rice, P, A., Lin, J,-S, L,, and Golenbock, D, T, (1997) J, Biol, Chem, 272, 10594-10600) allow us to present for the first time the complete structure of a major molecular species of a chlamydial LPS.