Antigen 85

Function

Antigens 85A, 85B and 85C posses mycolyltransferase activity and generate trehalose dimycolate which is an essential envelope lipid for Mycobacterium tuberculosis virulence. Inhibition of these enzymes hinders growth of the bacteria. The three enzymes show very high sequence identity (68-79%).

Disease

Antigen 85 proteins levels are elevated in tuberculosis patients.

Structural highlights

The 3D structures of the 3 antigens show that their active sites are virtually identical indicating that they share the same substrate. However, residues at the surface of the enzymes are different.