Structure of mycobactin J

Mycobactin J-1, an iron chelate fromMycobacterium paratuberculosis, was characterized by mass spectrum and by¹H nuclear magnetic resonance (NMR) and¹³C NMR spectra of the parent molecule and of cobactin J-1. The core structure of mycobactin J-1 contained the phenyloxazoline ring system common to the mycobactins. The benzene ring was disubstituted. The two hydroxamate functions were furnished by 1 linear 6-N-hydroxylysine residue and 1 cyclic 6-N-hydroxylysine residue as in other members of this class of compounds. The acyl function at the mycobactic acid hydroxamate center wasn-cis-hexadec-2-enoyl. The hydroxyacid of the cobactin portion of mycobactin J-1 was 2,4-dimethyl-3-hydroxypentanoic acid. This latter residue differs from those of other known mycobactins by the presence of the isopropyl group.