Fig. 9.

Biosynthetic pathway of LM (A) and LAM (B) biogenesis in Corynebacterineae. Cg-LM biosynthesis initially involves the formation of the α(1→6) mannan backbone by MptB, followed by α(1→2)-Manp branching by MptC (or MptD). This biosynthetic precursor would then be the substrate for further α(1→6)-Manp elongation by MptA, followed by α(1→2)-Manp branching by MptD (or MptC) to afford initially Cg-LM (A). Further extension by MptA along with additional GT-C glycosyltransferases further modify the α(1→6)-mannan backbone. These GT-Cs include MptC/D and MptE (formation of the dimannoside side-chain), and AftE/MptC/D and formation of Araf-Manp side-chains (B).