Antigen 85 complex protein A (Ag85A)

Antigen 85 complex protein A is one of three major secreted proteins (Ag85A, Ag85B, Ag85C) produced by *Mycobacterium tuberculosis* and related mycobacteria. It functions as a mycolyltransferase, catalyzing the transfer of mycolic acids in the synthesis of trehalose dimycolate, a key glycolipid essential for the integrity and pathogenicity of the mycobacterial cell wall[1][2][3][10]. Ag85A is highly immunogenic and participates in interactions with host extracellular matrix (binds fibronectin)[5][6][9][10]. Because of its essential function in cell wall assembly and its accessible location as a secreted protein, Ag85A is a validated drug target for novel tuberculosis treatments and a major antigen in vaccine development and diagnostic assays[3][4][8].

Other names

Fibronectin-binding protein AFbpA30-kDa major extracellular proteinRv3804c (gene locus in M. tuberculosis)

Covalent allosteric inhibition of mycolyltransferase activity through modification of a cysteine residue near the active site (e.g., by ebselen)