Comparison of Lipid A moieties obtained from Bordetella bronchiseptica LPS core mutants

ADRIANA CASABUONO; FEDERICO SISTI; DANIELA HOZBOR; ALICIA S. COUTO

Mendoza

Congreso; XLVIII reunion anual de SAIB; 2012

Soc. argentina deInvestigaciones en Bioquimica y Biologia Molecular

Comparison of Lipid A moieties obtained from Bordetella bronchiseptica LPS core mutants Adriana C. Casabuono1, Federico Sisti2, Daniela Hozbor2 and Alicia S. Couto1 1CIHIDECAR, Organic Chemistry Dep., FCEN-UBA, 2 IBBM, UNLP, CONICET, Argentina Bordetella bronchiseptica(Bb) can infect a variety of mammals including humans. Defective mutants of the lipopolysaccharide (LPS) structure are used to understand their role in bacteria?host interaction. On a Bb 9.73 background, three mutants were generated: BbLP39, defective in the expression of waaC gene which codes for a heptosyltransferase of the core region; Bb3394, defective in a gene involved in core substitution with a GalNAc and Bb3398, defective in the glucose transfer to the first heptose of the core. In this work the Lipid A moieties were released from the LPS mutants, analyzed by mass spectrometry and compared with the wild type strain. It was interesting to note that while the wild type strain presents a hexa-acylated diglucosamine backbone substituted with a phosphoglucosamine unit, lipid A from BbLP39 presented a pyrophosphate group. On the other hand, Lipid A obtained from Bb3394 mutant showed a hexa-acylated backbone carrying two phosphoglucosamine units. However, Bb3398 mutant showed a hexa-acylated backbone modified with phosphoethanolamine and pyrophosphorylethanolamine groups. How inactivation of genes involved in the core biosynthesis affects Lipid A structures is not clear. However these modifications are known to alter LPS toxicity as well as vary the charge of Lipid A involved in protection of the bacteria.