1408060-47-8Relevant articles and documents
Carbohydrate-lipid interactions: Affinities of methylmannose polysaccharides for lipids in aqueous solution
Liu, Lan,Bai, Yu,Sun, Nian,Xia, Li,Lowary, Todd L.,Klassen, John S.
supporting information, p. 12059 - 12067,9 (2012/12/12)
The interactions between 3-O-methyl-mannose polysaccharides (MMPs), extracted from Mycobacterium smegmatis (consisting of a mixture of MMP-10, -11, -12 and -13) or obtained by chemical synthesis (MMP-5s, -8 s, -11s and -14s), and linear saturated and unsaturated fatty acids (FAs), and a commercial mixture of naphthenic acids (NAs) in aqueous solution at 25°C and pHa 8.5 were quantified by electrospray ionization mass spectrometry (ESI-MS). Association constants (Ka) for MMP binding to four FAs (myristic acid, palmitic acid, stearic acid and trans-parinaric acid) were measured by using an indirect ESI-MS assay, the proxy protein method. The Ka values are in the 104-105 M-1 range and, based on results obtained for the binding of the synthetic MMPs with palmitic acid, increase with the size of the carbohydrate. Notably, the measured affinity of the extracted MMPs for trans-parinaric acid is two orders of magnitude smaller than the reported value, which was determined by using a fluorescence assay. Using a newly developed competitive binding assay, referred to as the proxy protein/proxy ligand ESI-MS method, it was shown that MMPs bind specifically to NAs in aqueous solution, with apparent affinities of approximately (5×104) M-1 for the mixture of NAs tested. This represents the first demonstration that MMPs can bind to hydrophobic species more complex than those containing linear alkyl/alkenyl chains. Moreover, the approach developed here represents a novel method for probing carbohydrate-lipid interactions. Copyright