A matrix-assisted laser desorption/ionization mass spectrometry approach of the Lipid A from Mesorhizobium loti.

A. C. CASABUONO; A. D’ANTUONO; Y. SATO; H. NONAMI; R. UGALDE; V. LEPEK; R. ERRA-BALSELLS; A. S. COUTO

RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM.

Wiley InterScience

Año: 2006 vol. 20 p. 2175 - 2182

0951-4198

ABSTRACT   The isolation, purification and analysis of the Lipid A obtained from Mesorhizobium loti Ayac 1 BII strain is presented. Different polyacylated species was evidenced by thin layer chromatography allowing the purification of two fractions. UV- matrix assisted laser desoption/ionization time-of-flight (UV-MALDI-TOF) mass spectrometry analysis with different matrices in the positive and negative ion mode, was performed. The fast moving component revealed the presence of hexa-acylated species, varying in the fatty acid composition. Species containing two OH-C15:0 fatty acids and two 27-OH-C28:0 fatty acids were observed. Individual ions within this family differ by + 14 mass units. The slow moving component was enriched mainly in penta-acylated species. Among them, two subgroups were detected: the major one bears two 3-OH 15:0 fatty acids, two 27 OH- 28:0 fatty acids and only one non-polar fatty acid. Each signal differ in a C12:0 acyl unit from the corresponding hexa-acylated family. On the other hand, the minor subgroup bears one 3-OH 15:0 fatty acid, one 27 OH-28:0 fatty acid and three non-polar fatty acids. The results obtained showed that nor-harmane resulted an excellent matrix for charged lipopolysaccharide studies in both, positive and negative ion modes.