Identification of a novel lipopolysaccharide biosynthesis gene in Bordetella bronchiseptica

CORDERO A; FERNÁNDEZ J.; CASABUONO AC; COUTO AC; HOZBOR D ; SISTI F

Mendoza

Congreso; XLVIII reunion anual de SAIB; 2012

Soc. argentina deInvestigaciones en Bioquimica y Biologia Molecular

Bordetella bronchiseptica is a respiratory pathogen of different mammals, including humans. The lipopolysaccharide (LPS) of this pathogen plays an important role in bacterial host interaction not only as adhesin but also in protection. Here we describe one particular gene BB3394 and confirmed its function as a glycoyltransferase involved in the biosynthesis of the core oligosaccharide. By insertionally inactivating this gene and studying the resulting LPS structure, we showed that BB3394 is involved in core lateral substitution with a GalNA. The MALDI-MS spectrum of the mutant BB3394 strain showed the highest mass species at m/z 1259.589 consistent with the core fragment (Hep)GlcN-Glc-(GlcNGlcAHep)Hep. The lack of higher m/z species would indicate the absence of the GalNA unit. The lateral position of this sugar explains previously described absence of differences in SDS PAGE profiles of the mutant compared to wild type LPS. With the description of Bb3394 only two more glucosiltransferases remain to be discovered in order to know all enzymes involved in LPS synthesis. Knowledge of this information is necessary to manipulate LPS structure in order to determinate the role of this important molecule in pathogenesis.