Carbohydrate epitope structural elucidation by 1H‐NMR spectroscopy of a new Mycobacterium kansasii phenolic glycolipid antigen

Abstract

The complete primary structure of the carbohydrate moiety of a new phenolic glycolipid antigen namely PheGl K‐IV from Mycobacterium kansasii was successfully established from only one‐ and two‐dimensional ¹H‐NMR data. Among the scalar two‐dimensional techniques, correlated spectroscopy with a 45° mixing pulse and phase‐sensitive double‐quantum‐filtered correlated spectroscopy were selected, combined with two‐dimensional dipolar techniques (nuclear Overhauser effect). These techniques using milligram of quantities native PheGl K‐IV allowed the following monoacetylated tetrasaccharide to be proposed for its carbohydrate part: The PheGl K‐IV shares, with the other phenolic glycolipids isolated from M. kansasii (K‐I, K‐II), a common core assigned to the lipid aglycone glycosylated by the monoacetylated trisaccharide part. It differs in the structure of the distal monosaccharide residue.