FIG. 4.

Structural analysis of methoxy- and ketomycolates from the ΔcmaA2 ΔmmaA2 strain. NMR analysis of purified methoxymycolate (A) or ketomycolate (B) from WT M. tuberculosis or the ΔcmaA2 ΔmmaA2 double mutant. The relative peak area of the cis cyclopropane peak at −0.33 is indicated below each spectrum and is set to 1.0 for the wild type. Spectra are normalized to the resonance at 0.86 (equal for the WT and the mutant), representing the terminal methyl groups common to all mycolic acids. Note that the ΔcmaA2 ΔmmaA2 strain also lacks trans cyclopropyl protons due to the cmaA2 deletion, as previously reported (9).