Abstract

PUPO, Elder  and  HARDY, Eugenio. Complexity and solutions to the isolation problem of Gram negative lipopolysaccharides' bacteria molecular species. Biotecnol Apl [online]. 2009, vol.26, n.1, pp.9-15. ISSN 1027-2852.

Gram negative bacteria frequently synthesize a great number of lipopolysaccharides (LPS) molecular species. The high LPS structural heterogeneity and its trend to conform molecular aggregates make the fraction of its molecular species extremely difficult. The application of chromatographic methods individually has allowed the obtainment of little homogeneous LPS fractions. With the combination of orthogonal chromatographic principles, only the purification of the simplest rough type LPS up to chemical homogeneity has been reached. This has determined that efforts aimed at more homogeneous LPS isolation is focused on the use of electrophoresis in slab gel. Electrophoresis methods are capable of separating species of similar molecular masses next to from the most complex smooth type LPS. Consequently upon this basis, a new methodology allowing the isolation of intact LPS of either rough or smooth types up to electrophoretic homogeneity has been developed. Under such methodology, sensible structural analysis through mass spectrometry and LAL (Limulus Amebocyte Lysate) activity of LPS individual species is feasible, composed of just a few chemical species. This methodology has proved the possible way of combining electrophoresis with other orthogonal separation principles, a further step which could guarantee the obtainment of chemically homogeneous preparations from complex LPS mixtures.

Keywords : lipopolysaccharides; isolation; chromatography; electrophoresis; reverse staining; elution; mass spectrometr.

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