Mycobacterium avium complex arabinosyltransferase EmbC (EmbC)

Mycobacterium avium complex arabinosyltransferase EmbC is a vital membrane-associated enzyme involved in the assembly of the mycobacterial cell envelope. It specifically facilitates the polymerization of the arabinan domain of lipoarabinomannan (LAM), a major lipoglycan that plays a crucial role in modulating the host immune response and promoting bacterial persistence [1][3]. EmbC functions by transferring arabinosyl residues from the donor molecule decaprenyl-phospho-arabinose (DPA) to growing carbohydrate chains [2][5]. This enzyme is the primary target of ethambutol, a cornerstone antibiotic used in the treatment of Mycobacterium avium complex (MAC) infections and tuberculosis [4]. Inhibition of EmbC results in the synthesis of truncated LAM molecules, which destabilizes the cell wall and increases the pathogen's susceptibility to environmental stressors and host defenses [3][5]. Because EmbC is unique to the Actinobacteria phylum and has no human homolog, it represents an ideal target for highly specific antimicrobial therapy [1][2].

Other names

EmbCArabinosyltransferase CLAM-synthesis arabinosyltransferaseMycobacterium avium EmbC

Ethambutol acts as a competitive inhibitor of the arabinosyltransferase EmbC by mimicking the substrate decaprenyl-phospho-arabinose (DPA), thereby preventing the polymerization of arabinan chains in the cell wall [2][4].