Figure 1. Schematic representation of the Mtb cell envelope.

Many of the classes of lipids and glycolipids discussed in the text are represented schematically and are shown in probable locations in the cell envelope. The structures with light and dark green hexagons represent trehalose mono- and dimycolates, respectively, the red lollipops represent phthiocerol dimycocerosates, while the gold ones represent sulfolipids, diacyltrehaloses and polyacyltrehaloses. Grey circles represent phospholipid headgroups, black circles, isoprenoids, light blue squares GlcNAc, white squares MurNAc, white pentagons arabinofuranose, yellow diamonds galactofuranose, and blue hexagons mannose. The overall schematic and individual structures are not drawn to scale and the numbers of carbohydrate residues shown are not representative of the actual molecules. Proteins and peptides are not shown for the sake of clarity.