2.1.1.365 Biosynthesis of mycobacterial methylmannose polysaccharides requires a unique 1-O-methyltransferase specific for 3-O-methylated mannosides Mycolicibacterium hassiacum 2.1.1.365 Biosynthesis of mycobacterial methylmannose polysaccharides requires a unique 1-O-methyltransferase specific for 3-O-methylated mannosides Mycolicibacterium hassiacum DSM 44199