Direct evidence of methylglucose lipopolysaccharides/palmitoyl-CoA noncovalent complexes by capillary zone electrophoresis-electrospray/mass spectrometry.
Mycobacterial methylglucose lipopolysaccharides (MGLPs) play an important regulatory role in the biosynthesis of long-chain fatty acids by forming complexes with neosynthesized acyl-CoA fatty acid derivatives. The MGLPs from Mycobacterium smegmatis were purified by high-performance anion-exchange chromatography and characterized by LSIMS and CE/ESI-MS. We investigated their interaction with palmitoyl-CoA using capillary zone electrophoresis with both direct and indirect UV detection. In the latter mode, the signal of the UV-transparent MGLPs decreased upon addition of increasing amounts of palmitoyl-CoA; while using direct UV detection, the addition of palmitoyl-CoA to the MGLPs revealed characteristic profiles. The major peak was assigned to the noncovalent MGLP/palmitoyl-CoA complex on the basis of its electrophoretic mobility. The abundance of the complex was found to increase until the MGLP/palmitoyl-CoA molar ratio reached a 1/1 stoichiometry. The existence of and the stoichiometry of this complex were assessed by CE/ESI mass spectrum analysis, showing pseudomolecular ions of the MGLP/palmitoyl-CoA complex. These results confirm that CE/ESI-MS is a powerful tool to characterize noncovalent molecular association.
Tuffal
G
G
Institut de Pharmacologie et Biologie Structurale, CNRS, Toulouse, France.
Tuong
A
A
Dhers
C
C
Uzabiaga
F
F
Rivière
M
M
Picard
C
C
Puzo
G
G
D019075:Electrophoresis, Capillary; D008070:Lipopolysaccharides / Q000032:analysis*; D013058:Mass Spectrometry; D008757:Methylglucosides / Q000032:analysis*; D010171:Palmitoyl Coenzyme A / Q000032:analysis*
D008070:Lipopolysaccharides; D008757:Methylglucosides; D010171:Palmitoyl Coenzyme A; C027020:methylglucoside